Microwave Plasma-Activated Chemical Vapor Deposition of Nitrogen-Doped Diamond. I. N2/H2 and NH3/H2 PlasmasClick to copy article linkArticle link copied!
- Benjamin S. Truscott
- Mark W. Kelly
- Katie J. Potter
- Mack Johnson
- Michael N. R. Ashfold
- Yuri A. Mankelevich
Abstract
We report a combined experimental/modeling study of microwave activated dilute N2/H2 and NH3/H2 plasmas as a precursor to diagnosis of the CH4/N2/H2 plasmas used for the chemical vapor deposition (CVD) of N-doped diamond. Absolute column densities of H(n = 2) atoms and NH(X3Σ–, v = 0) radicals have been determined by cavity ring down spectroscopy, as a function of height (z) above a molybdenum substrate and of the plasma process conditions, i.e., total gas pressure p, input power P, and the nitrogen/hydrogen atom ratio in the source gas. Optical emission spectroscopy has been used to investigate variations in the relative number densities of H(n = 3) atoms, NH(A3Π) radicals, and N2(C3Πu) molecules as functions of the same process conditions. These experimental data are complemented by 2-D (r, z) coupled kinetic and transport modeling for the same process conditions, which consider variations in both the overall chemistry and plasma parameters, including the electron (Te) and gas (T) temperatures, the electron density (ne), and the plasma power density (Q). Comparisons between experiment and theory allow refinement of prior understanding of N/H plasma-chemical reactivity, and its variation with process conditions and with location within the CVD reactor, and serve to highlight the essential role of metastable N2(A3Σ+u) molecules (formed by electron impact excitation) and their hitherto underappreciated reactivity with H atoms, in converting N2 process gas into reactive NHx (x = 0–3) radical species.
1 Introduction
2 Experimental Methods
3 Experimental Results
4 N/H Plasma Modeling
rate coefficient k = ATb exp(−E/RT) | |||||
---|---|---|---|---|---|
reaction | A | b | E | Rforward/(cm–3 s) | Rreverse/(cm–3 s) |
H + H + H2 ⇌ H2 + H2 | 9.00 × 1016 | –0.6 | 0 | 1.179 × 1018 | 1.354 × 1019 |
H + H + H ⇌ H2 + H | 1.00 × 1018 | –1 | 0 | 4.042 × 1016 | 4.641 × 1017 |
NH3 + H ⇌ NH2 + H2 | 5.40 × 105 | 2.4 | 9915 | 1.409 × 1018 | 1.410 × 1018 |
NH2 + H ⇌ NH + H2 | 4.00 × 1013 | 0 | 3650 | 4.379 × 1017 | 4.390 × 1017 |
NH + H ⇌ N + H2 | 1.88 × 108 | 1.55 | 205 | 7.205 × 1017 | 7.206 × 1017 |
N + NH ⇌ N2 + H | 3.00 × 1013 | 0 | 0 | 5.094 × 1012 | 5.655 × 1011 |
N + NH2 ⇌ N2 + H + H | 7.26 × 1013 | 0 | 0 | 1.481 × 1013 | 1.436 × 1011 |
N + NH2 ⇌ N2H + H | 1.00 × 1013 | 0 | 0 | 2.039 × 1012 | 2.277 × 1011 |
NH + NH ⇌ N2 + H + H | 5.10 × 1013 | 0 | 0 | 7.523 × 1012 | 7.277 × 1010 |
NH + NH ⇌ N2H + H | 8.00 × 1011 | 0.5 | 1987 | 4.478 × 1012 | 4.989 × 1011 |
NH + NH2 ⇌ N2H2 + H | 4.27 × 1014 | –0.272 | –77 | 8.784 × 1012 | 3.406 × 1012 |
NH2 + NH2 ⇌ N2H2 + H2 | 1.70 × 108 | 1.62 | 11783 | 1.861 × 1012 | 7.234 × 1011 |
NH2 + NH3 ⇌ N2H4 + H | 19 | 3.11 | 50115 | 1.303 × 108 | 3.458 × 107 |
N2H4 + H ⇌ N2H3 + H2 | 4.54 × 107 | 1.8 | 2613 | 6.459 × 108 | 9.143 × 108 |
N2H3 + H ⇌ N2H2 + H2 | 2.40 × 108 | 1.5 | –10 | 8.725 × 109 | 9.042 × 109 |
N2H2 + H ⇌ N2H + H2 | 3.60 × 108 | 1.58 | 1717 | 8.158 × 1012 | 2.350 × 1012 |
N2H + H ⇌ N2 + H2 | 3.60 × 108 | 1.58 | 1717 | 3.673 × 1015 | 3.662 × 1015 |
NH2 + NH2 ⇌ NH + NH3 | 5.616 | 3.53 | 555 | 1.770 × 1012 | 1.773 × 1012 |
NH + M ⇌ N + H + M | 2.65 × 1014 | 0 | 75 500 | 1.156 × 1014 | 1.007 × 1013 |
NH2 + M ⇌ NH + H + M | 3.16 × 1023 | –2 | 91 400 | 1.241 × 1015 | 1.084 × 1014 |
NH3 + M ⇌ NH2 + H + M | 2.20 × 1016 | 0 | 93 468 | 1.770 × 1015 | 1.544 × 1014 |
N2H2 + M ⇌ N2H + H + M | 1.90 × 1027 | –3.5 | 66 107 | 7.238 × 1011 | 1.816 × 1010 |
NH + N ⇌ N2(A3) + H | 4.50 × 1010 | 0 | 0 | 7.641 × 109 | 1.233 × 1014 |
N2(A3) + H ⇌ N2 + H | 1.26 × 1014 | 0 | 0 | 2.538 × 1016 | 1.746 × 1011 |
N2(A3) + H2 ⇌ N2 + H + H | 5.00 × 1012 | 0 | 4450 | 6.203 × 1015 | 3.717 × 109 |
N2(A3) + NH3 ⇌ NH2 + H + N2 | 7.47 × 1013 | 0 | 0 | 5.475 × 1011 | 3.284 × 105 |
N + N + H2 ⇌ N2(A3) + H2 | 5.00 × 1013 | 0 | –997 | 9.008 × 106 | 1.669 × 1012 |
N + N + N2 ⇌ N2(A3) + N2 | 3.00 × 1014 | 0 | –997 | 1.701 × 105 | 3.152 × 1010 |
H(n = 3) → H(n = 2) + hν | 4.40 × 107 | 0 | 0 | 2.766 × 1014 | |
H(n = 2) → H + hν | 4.70 × 108 | 0 | 0 | 2.956 × 1016 | |
H(n = 3) → H + hν | 5.50 × 107 | 0 | 0 | 3.457 × 1014 | |
H2* → H2 + hν | 2.00 × 107 | 0 | 0 | 3.317 × 1016 | |
H2(v = 1) + H → H2(v = 0) + H | 1.26 × 109 | 1.35 | 2200 | 1.210 × 1023 | |
H2(v = 0) + H → H2(v = 1) + H | 1.26 × 109 | 1.35 | 14 089 | 1.208 × 1023 | |
H2(v = 1) + H2 → H2(v = 0) + H2 | 1.88 × 107 | 1.5 | 9550 | 2.213 × 1022 | |
H2(v = 0) + H2 → H2(v = 1) + H2 | 1.88 × 107 | 1.5 | 21 439 | 2.210 × 1022 | |
H(n = 2) + H2 → H + H + H | 1.00 × 1013 | 0 | 0 | 4.872 × 1014 | |
H(n = 3) + H2 → H + H + H | 1.00 × 1013 | 0 | 0 | 4.869 × 1013 | |
H(n = 2) + H2 → H3+ + e | 1.00 × 1013 | 0 | 16 130 | 2.914 × 1013 | |
H(n = 3) + H2 → H3+ + e | 1.00 × 1013 | 0 | 0 | 4.869 × 1013 | |
H2+ + H2 → H3+ + H | 1.20 × 1015 | 0 | 0 | 3.242 × 1014 | |
H2+ + N2 → N2H+ + H | 1.20 × 1015 | 0 | 0 | 1.021 × 1012 | |
H3+ + N2 → N2H+ + H2 | 1.08 × 1015 | 0 | 0 | 5.663 × 1014 | |
H3+ + NH3 → NH4+ + H2 | 1.63 × 1015 | 0 | 0 | 7.330 × 1011 | |
H+ + H2 + H2 → H3+ + H2 | 3.60 × 1019 | –0.5 | 0 | 1.651 × 1014 | |
N2+ + H2 → N2H+ + H | 1.20 × 1015 | 0 | 0 | 1.303 × 1012 | |
N2H+ + NH3 → NH4+ + N2 | 1.38 × 1015 | 0 | 0 | 3.081 × 1014 | |
NH3+ + H2 → NH4+ + H | 1.20 × 1012 | 0 | 0 | 3.560 × 1011 |
rate constant k = ATeb exp(−E/(RTe)) | ||||
---|---|---|---|---|
electron reactions | A | b | E | |
H(n = 2) + e → H(n = 3) + e | 2.53 × 1016 | 0 | 43 775 | 1.059 × 1011 |
H(n = 3) + e → H(n = 2) + e | 3.10 × 1016 | 0 | 0 | 6.220 × 1010 |
H + e → H(n = 2) + e | 1.21 × 1016 | 0 | 235 001 | 2.980 × 1016 |
H(n = 2) + e → H + e | 1.17 × 1016 | 0 | 0 | 2.348 × 1011 |
H + e → H(n = 3) + e | 1.39 × 1015 | 0 | 278 545 | 7.197 × 1014 |
H2(v = 0) + e → H2(v = 1) + e | 2.00 × 1015 | 0 | 11 980 | 1.725 × 1020 |
H2(v = 1) + e → H2(v = 0) + e | 2.30 × 1015 | 0 | 0 | 3.826 × 1019 |
H2 + e → H + H + e | 2.43 × 1015 | 0 | 191 226 | 3.841 × 1017 |
H2 + e → H + H + e | 8.88 × 1015 | 0 | 267 260 | 9.203 × 1016 |
H2 + e → H2* + e | 3.20 × 1015 | 0 | 267 260 | 3.317 × 1016 |
H2* + e → H2 + e | 1.00 × 1015 | 0 | 0 | 5.302 × 1011 |
N2 + e → N + N + e | 5.12 × 1014 | 0 | 282 231 | 9.772 × 1012 |
N2 + e → N + N + e | 1.87 × 1015 | 0 | 287 991 | 2.900 × 1013 |
NH3 + e → NH2 + H + e | 1.20 × 1016 | 0 | 184 000 | 6.667 × 1012 |
NH2 + e → NH + H + e | 1.20 × 1016 | 0 | 184 000 | 1.884 × 1012 |
N2 + e → N2(A3) + e | 1.10 × 1016 | 0 | 142 153 | 3.171 × 1016 |
H2* + e → H2+ + e + e | 4.84 × 1015 | 0 | 88 241 | 1.087 × 1011 |
H + e → H+ + e + e | 1.11 × 1015 | 0 | 313 330 | 1.651 × 1014 |
H2 + e → H2+ + e + e | 7.23 × 1014 | 0 | 354 810 | 3.251 × 1014 |
N2 + e → N2+ + e + e | 1.09 × 1015 | 0 | 359 413 | 1.303 × 1012 |
NH3 + e → NH3+ + e + e | 6.81 × 1015 | 0 | 249 976 | 3.560 × 1011 |
H2+ + e → H(n = 2) + H | 5.00 × 1018 | –0.67 | 0 | 9.277 × 108 |
H3+ + e → H2 + H(n = 2) | 2.89 × 1014 | 0 | 0 | 1.980 × 1010 |
N2H+ + e → N2 + H | 2.50 × 1019 | –0.9 | 0 | 1.569 × 1014 |
NH4+ + e → NH3 + H | 3.00 × 1018 | –0.67 | 0 | 1.375 × 1014 |
NH4+ + e → NH2 + H + H | 3.00 × 1018 | –0.67 | 0 | 1.375 × 1014 |
N2(A3) represents the metastable A3Σu+ state (the lowest energy triplet state) of N2. The last two columns show the forward and reverse reaction rates calculated in the core (i.e., r = 0, z = 10.5 mm) of a 1.2% N2/H2 plasma with T = 2882 K and Te = 1.21 eV (14 042 K), for P = 1.5 kW and p = 150 Torr. Units: cal, cm, s, K, R = 1.987 262 cal (mol K)−1, M is a third body, and the gas temperature T and electron temperature Te are quoted in K.
4.1 N2/H2 and NH3/H2 Plasma Activation and Dependences on X0(N)
4.1.1 N2/H2 Mixtures
4.1.2 NH3/H2 Mixtures
mixture | 1.2% N2 in H2 | 1.2% NH3 in H2 | ||
---|---|---|---|---|
z/mm | 8.0 | 0.5 | 8.0 | 0.5 |
T /K | 2799 | 1354 | 2821 | 1364 |
H2 | 4.85 × 1017 | 1.06 × 1018 | 4.81 × 1017 | 1.05 × 1018 |
N2 | 1.54 × 1015 | 5.51 × 1015 | 7.48 × 1014 | 2.68 × 1015 |
e | 2.09 × 1011 | 6.76 × 1010 | 2.22 × 1011 | 7.52 × 1010 |
H(n = 1) | 3.09 × 1016 | 7.50 × 1015 | 3.19 × 1016 | 7.83 × 1015 |
H(n = 2) | 7.05 × 107 | 1.97 × 106 | 8.39 × 107 | 2.49 × 106 |
H(n = 3) | 7.21 × 106 | 1.47 × 105 | 8.72 × 106 | 1.89 × 105 |
N2(A3) | 4.79 × 109 | 7.66 × 109 | 2.53 × 109 | 4.26 × 109 |
N2H | 5.58 × 108 | 1.94 × 107 | 3.14 × 108 | 4.22 × 107 |
N2H2 | 2.03 × 106 | 6.07 × 106 | 5.46 × 106 | 1.33 × 107 |
NH3 | 1.58 × 1012 | 8.94 × 1012 | 2.63 × 1012 | 1.28 × 1013 |
NH2 | 3.75 × 1011 | 1.12 × 1011 | 6.53 × 1011 | 1.70 × 1011 |
NH | 2.87 × 1011 | 1.11 × 1011 | 5.11 × 1011 | 1.71 × 1011 |
N | 3.20 × 1011 | 1.35 × 1012 | 5.74 × 1011 | 2.04 × 1012 |
H2+ | 4.79 × 105 | 3.33 × 104 | 5.74 × 105 | 4.24 × 104 |
H3+ | 2.69 × 108 | 8.36 × 106 | 6.62 × 108 | 2.34 × 107 |
N2H+ | 1.13 × 1011 | 2.46 × 1010 | 9.32 × 1010 | 2.06 × 1010 |
NH4+ | 9.52 × 1010 | 4.30 × 1010 | 1.28 × 1011 | 5.45 × 1010 |
4.2 Variations with Applied MW Power and Total Gas Pressure
4.2.1 Power Dependences
4.2.2 Pressure Dependences
5 Summary and Conclusions
Acknowledgment
The Bristol authors gratefully acknowledge financial support from the Engineering and Physical Sciences Research Council (EPSRC, Grants EP/H043292/1 and EP/K018388/1) and Element Six Ltd., and the many and varied contributions from colleagues Dr. C. M. Western, Dr. J. A. Smith, and K. N. Rosser. Yu.A.M. is grateful to Act 220 of the Russian Government (Agreement No. 14.B25.31.0021 with the host organization IAPRAS).
Appendix
References
This article references 43 other publications.
- 1Breeding, C. M.; Shigley, J. E. The ‘Type’ Classification System of Diamonds and its Importance in Gemology Gems Gemol. 2009, 45, 96– 111 DOI: 10.5741/GEMS.45.2.96Google Scholar1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXpvF2ns7g%253D&md5=e2a02c3b8cab00e67566513f8e384d6fThe "type" classification system of diamonds and its importance in gemologyBreeding, Christopher M.; Shigley, James E.Gems and Gemology (2009), 45 (2), 96-111CODEN: GEGEA2; ISSN:0016-626X. (Gemological Institute of America)A review. Diamond "type" is a concept that is frequently mentioned in the gemol. literature, but its relevance to the practicing gemologist is rarely discussed. Diamonds are broadly divided into two types (I and II) based on the presence or absence of nitrogen impurities, and further subdivided according to the arrangement of nitrogen atoms (isolated or aggregated) and the occurrence of boron impurities. Diamond type is directly related to color and the lattice defects that are modified by treatments to change color. Knowledge of type allows gemologists to better evaluate if a diamond might be treated or synthetic, and whether it should be sent to a lab. for testing. Scientists det. type using expensive FTIR instruments, but many simple gemol. tools (e.g., a microscope, spectroscope, UV lamp) can give strong indications of diamond type.
- 2Tallaire, A.; Collins, A. T.; Charles, D.; Achard, J.; Sussmann, R.; Gicquel, A.; Newton, M. E.; Edmonds, A. M.; Cruddace, R. J. Characterisation of High-quality Thick Single-crystal Diamond Grown by CVD with Low Nitrogen Content Diamond Relat. Mater. 2006, 15, 1700– 1707 DOI: 10.1016/j.diamond.2006.02.005Google Scholar2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVSisLfO&md5=9d733985730097daf389f8359d6a1750Characterisation of high-quality thick single-crystal diamond grown by CVD with a low nitrogen additionTallaire, A.; Collins, A. T.; Charles, D.; Achard, J.; Sussmann, R.; Gicquel, A.; Newton, M. E.; Edmonds, A. M.; Cruddace, R. J.Diamond and Related Materials (2006), 15 (10), 1700-1707CODEN: DRMTE3; ISSN:0925-9635. (Elsevier B.V.)Single-crystal homoepitaxial diamond was grown by CVD using a high-d. microwave plasma. The growth rate can be increased by factors of ≤2.5 by adding small concns. (2-10 ppm) of N to the gas phase. Free-standing specimens ≤1.7 mm thick were characterized using optical absorption, cathodoluminescence, photoluminescence, and Raman spectroscopies, and by ESR. These techniques all demonstrate that the colorless type IIa material is of excellent quality with total defect concns. not exceeding 200 ppb, and is ideally suited for optical and electronic applications.
- 3Chayahara, A.; Mokuno, Y.; Horino, Y.; Takasu, Y.; Kato, H.; Yoshikawa, H.; Fujimori, N. The Effect of Nitrogen Addition during High-rate Homoepitaxial Growth of Diamond by Microwave Plasma CVD Diamond Relat. Mater. 2004, 13, 1954– 1958 DOI: 10.1016/j.diamond.2004.07.007Google Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXpt1WlsLk%253D&md5=6e9c894e0a185e89c59012e1ac8885ecThe effect of nitrogen addition during high-rate homoepitaxial growth of diamond by microwave plasma CVDChayahara, A.; Mokuno, Y.; Horino, Y.; Takasu, Y.; Kato, H.; Yoshikawa, H.; Fujimori, N.Diamond and Related Materials (2004), 13 (11-12), 1954-1958CODEN: DRMTE3; ISSN:0925-9635. (Elsevier B.V.)The effect of nitrogen addn. on growth rate, morphol. and crystallinity during high-rate microwave plasma chem. vapor deposition (MPCVD) of diamond was investigated. Epitaxial diamond was grown on type Ib diamond (100) substrates using a 5-kW, 2.45-GHz microwave plasma CVD system with nitrogen addn. in the methane and hydrogen source gases. In order to obtain high growth rates, we designed the substrate holders to generate high-d. plasma. The growth rates ranged from 30 to 120 μm/h. The nitrogen addn. enhanced the growth rate by a factor of 2 and was beneficial to create a macroscopic smooth (100) face avoiding the growth of hillocks. However, the (100) surfaces looked microscopically rough by bunched steps as the effect of nitrogen addn. The macroscopic smoothing during the growth enabled the long-term stable deposition required to obtain large crystals. The deposited diamond was characterized by optical microscope, Raman spectroscopy, cathodoluminescence spectroscopy and X-ray diffraction.
- 4Lu, J.; Gu, Y.; Grotjohn, T. A.; Schuelke, T.; Asmussen, J. Experimentally Defining the Safe and Efficient, High Pressure Microwave Plasma Assisted CVD Operating Regime for Single Crystal Diamond Synthesis Diamond Relat. Mater. 2013, 37, 17– 28 DOI: 10.1016/j.diamond.2013.04.007Google Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXpvVeqtrc%253D&md5=56f2193c7248d0621e007c997628a229Experimentally defining the safe and efficient, high pressure microwave plasma assisted CVD operating regime for single crystal diamond synthesisLu, J.; Gu, Y.; Grotjohn, T. A.; Schuelke, T.; Asmussen, J.Diamond and Related Materials (2013), 37 (), 17-28CODEN: DRMTE3; ISSN:0925-9635. (Elsevier B.V.)The detailed exptl. behavior of a microwave plasma assisted CVD (MPACVD) reactor operating within the high, 180-300 torr, pressure regime is presented. An exptl. methodol. is described that 1st defines the reactor operating field map and then enables, while operating at these high pressures, the detn. of the efficient, safe and discharge stable diamond synthesis process window. Within this operating window discharge absorbed power densities of 300-1000 W/cm3 are achieved and high quality, single crystal diamond (SCD) synthesis rates of 20-75 μm/h are demonstrated. The influence of several input exptl. variables including pressure, N2 concn., CH4 percentage and substrate temp. on SCD deposition is explored. At a const. pressure of 240 torr, a high quality, high growth rate SCD synthesis window vs. substrate temp. is exptl. identified between 1030 and 1250°. When the input N impurity level is reduced <10 ppm in the gas phase the quality of the synthesized diamond is IIa or better.
- 5Bogdanov, S.; Vikharev, A.; Gorbachev, A.; Muchnikov, A.; Radishev, D.; Ovechkin, N.; Parshin, V. Growth-rate Enhancement of High-quality, Low-loss CVD-produced Diamond Disks Grown for Microwave Windows Application Chem. Vap. Deposition 2014, 20, 32– 38 DOI: 10.1002/cvde.201307058Google Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjslWku74%253D&md5=e06b2e9df3cb7f20175d28bbffe7daf3Growth-rate Enhancement of High-quality, Low-loss CVD-produced Diamond Disks Grown for Microwave Windows ApplicationBogdanov, Sergey; Vikharev, Anatoly; Gorbachev, Aleksei; Muchnikov, Anatoly; Radishev, Dmitry; Ovechkin, Nikolai; Parshin, VladimirChemical Vapor Deposition (2014), 20 (1-2-3), 32-38CODEN: CVDEFX; ISSN:0948-1907. (Wiley-Blackwell)The effect of nitrogen addn. on the growth rate, quality, and properties of polycryst. diamond grown by microwave plasma assisted (MPA)CVD is investigated. Two series of expts. are performed at two different microwave power densities (40 and 110 W cm-3) using a 2.45 GHz cylindrical microwave reactor. The results show that the beneficial effect of nitrogen is more distinct at higher microwave power densities. To investigate the properties of polycryst. diamond grown with nitrogen addn., a thick diamond disk of 50 mm diam. is grown with an addn. of 50 ppm nitrogen using a 2.45 GHz ellipsoidal microwave reactor. The grown diamond disk has a thermal cond. of 17.3 W cm-1 K-1 and dielec. loss tangent of 3.7 × 10-5 at a frequency of 170 GHz, and its parameters are suitable for application in microwave windows (e.g., gyrotron windows). Our results indicate that it is possible to achieve the increased (by a factor of 2.5) growth rates by nitrogen addn. without significant degrdn. of diamond quality, and properties such as thermal cond. and dielec. loss tangent.
- 6Achard, J.; Silva, F.; Brinza, O.; Tallaire, A.; Gicquel, A. Coupled Effect of Nitrogen Addition and Surface Temperature on the Morphology and the Kinetics of Thick CVD Diamond Single Crystals Diamond Relat. Mater. 2007, 16, 685– 689 DOI: 10.1016/j.diamond.2006.09.012Google Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXkt1alt7w%253D&md5=4c1dd701816ab0a9ae2d7cb01047c9cbCoupled effect of nitrogen addition and surface temperature on the morphology and the kinetics of thick CVD diamond single crystalsAchard, J.; Silva, F.; Brinza, O.; Tallaire, A.; Gicquel, A.Diamond and Related Materials (2007), 16 (4-7), 685-689CODEN: DRMTE3; ISSN:0925-9635. (Elsevier B.V.)In this study, homoepitaxial thick diamond films were grown by CVD at high microwave power densities for temps. ranging from 800° to 950° and with nitrogen addns. from 75 to 200 ppm relative to the total gas flow. There is a coupled effect of these two parameters on the growth mechanisms of the CVD diamond film. For a deposition temp. close to 875° and for the lowest nitrogen concn., the growth proceeded via a step flow mode identified by classical step bunching phenomena due to the presence of nitrogen and leading to the appearance of macro-steps. When nitrogen concn. was increased keeping the same temp., the growth mode evolved from a step flow mode to a bidimensional nucleation mode, for which macro-steps are no longer obsd. For higher growth temps. (950°), this growth mode transition still exists but appears for much higher nitrogen concn. These different observations, assocd. with the resulting growth rates, are discussed in terms of surface modification induced by the presence of nitrogen impurity. It is shown in particular that an increase of nitrogen concn. is equiv. to an increase of the surface supersatn., this effect being compensated by an increase of the deposition temp.
- 7Vandevelde, T.; Wu, T. D.; Quaeyhaegens, C.; Vlekken, J.; D’Olieslaeger, M.; Stals, L. Correlation Between the OES Plasma Composition and the Diamond Film Properties during Microwave PA-CVD with Nitrogen Addition Thin Solid Films 1999, 340, 159– 163 DOI: 10.1016/S0040-6090(98)01410-2Google ScholarThere is no corresponding record for this reference.
- 8Smith, J. A.; Rosser, K. N.; Yagi, H.; Wallace, M. I.; May, P. W.; Ashfold, M. N. R. Diamond Deposition in a DC-arc Jet CVD System: Investigations of the Effects of Nitrogen Addition Diamond Relat. Mater. 2001, 10, 370– 375 DOI: 10.1016/S0925-9635(00)00444-1Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjtFeltbc%253D&md5=42031dd16b270649b184172dd8543860Diamond deposition in a DC-arc Jet CVD system: investigations of the effects of nitrogen additionSmith, J. A.; Rosser, K. N.; Yagi, H.; Wallace, M. I.; May, P. W.; Ashfold, M. N. R.Diamond and Related Materials (2001), 10 (3-7), 370-375CODEN: DRMTE3; ISSN:0925-9635. (Elsevier Science S.A.)Studies of the CVD of diamond films at growth rates >100 μm h-1 with a 10-kW DC-arc jet system are described. Addns. of small amts. of N2 to the std. CH4/H2/Ar feedstock gas results in strong CN(B X) emission, and quenches C2(d a) and Hα emissions from the plasma. Species selective, spatially resolved optical emission measurements have enabled derivation of the longitudinal and lateral variation of emitting C2, CN radicals and H (n = 3) atoms within the plasma jet. SEM and laser Raman analyses indicate that N2 addns. also degrade both the growth rate and quality of the deposited diamond film; the latter technique also provides some evidence for N inclusion within the films.
- 9Truscott, B. S.; Kelly, M. W.; Potter, K. J.; Ashfold, M. N. R.; Mankelevich, Yu. A. Microwave Plasma Enhanced Chemical Vapour Deposition of Nitrogen Doped Diamond, II: CH4/N2/H2 Plasmas. J. Phys. Chem. A (awaiting submission).Google ScholarThere is no corresponding record for this reference.
- 10Mankelevich, Yu. A.; Ashfold, M. N. R.; Ma, J. Plasma-chemical Processes in Microwave Plasma Enhanced Chemical Vapour Deposition Reactors Operating with C/H/Ar Gas Mixtures J. Appl. Phys. 2008, 104, 113304 DOI: 10.1063/1.3035850Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsFWitrzJ&md5=5ad12124fa9fa38815eb284be3c2f911Plasma-chemical processes in microwave plasma-enhanced chemical vapor deposition reactors operating with C/H/Ar gas mixturesMankelevich, Yuri A.; Ashfold, Michael N. R.; Ma, JieJournal of Applied Physics (2008), 104 (11), 113304/1-113304/11CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Microwave (MW) plasma-enhanced CVD (PECVD) reactors are widely used for growing diamond films with grain sizes spanning the range from nanometers through microns to millimeters. This paper presents a detailed description of a two-dimensional model of the plasma-chem. activation, transport, and deposition processes occurring in MW activated H/C/Ar mixts., focusing particularly on the following base conditions: 4.4%CH4/7%Ar/balance H2, pressure p = 150 torr, and input power P = 1.5 kW. The model results are verified and compared with a range of complementary exptl. data in the companion papers. These comparators include measured (by cavity ring down spectroscopy) C2(a), CH(X), and H(n = 2) column densities and C2(a) rotational temps., and IR (quantum cascade laser) measurements of C2H2 and CH4 column densities under a wide range of process conditions. The model allows identification of spatially distinct regions within the reactor that support net CH4 → C2H2 and C2H2 → CH4 conversions, and provide a detailed mechanistic picture of the plasma-chem. transformations occurring both in the hot plasma and in the outer regions. Semi-anal. expressions for estg. relative concns. of the various C1Hx species under typical MW PECVD conditions are presented, which support the consensus view regarding the dominant role of CH3 radicals in diamond growth under such conditions. (c) 2008 American Institute of Physics.
- 11Kelly, M. W.; Halliwell, S. C.; Rodgers, J.; Pattle, J. D.; Harvey, J. N.; Ashfold, M. N. R. Theoretical Investigations of the Reactions of N and O Containing Species on a C(100):H 2 × 1 Reconstructed Diamond Surface. J. Phys. Chem. A (awaiting submission).Google ScholarThere is no corresponding record for this reference.
- 12Gordiets, B.; Ferreira, C. M.; Pinheiro, M. J.; Ricard, A. Self-consistent Kinetic Model of Low Pressure N2-H2 Flowing Discharges: I. Volume Processes Plasma Sources Sci. Technol. 1998, 7, 363– 378 DOI: 10.1088/0963-0252/7/3/015Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXos1Whtw%253D%253D&md5=6528796615defecd8c173b8bc988971fSelf-consistent kinetic model of low-pressure N2-H2 flowing discharges: I. Volume processesGordiets, B.; Ferreira, C. M.; Pinheiro, M. J.; Ricard, A.Plasma Sources Science & Technology (1998), 7 (3), 363-378CODEN: PSTEEU; ISSN:0963-0252. (Institute of Physics Publishing)This work is the 1st of two companion papers devoted to the kinetic modeling of low-pressure d.c. flowing discharges in N2-H2 mixts. While the present paper is mainly concerned with bulk discharge processes, the 2nd one studies surface processes involving dissocd. N and H atoms, which are essential to understand the discharge properties. The global model combining bulk and surface processes as described in these two papers is self-contained in the sense that the sole input parameters it requires are those that can externally be chosen in expts., namely: total gas pressure, radius and length of the discharge tube, discharge current, gas flow rate and initial gas temp. and compn. (e.g., the relative hydrogen concn. X in the binary mixt. (1 - X)N2 + XH2 at the discharge inlet). For a given set of input parameters, this model enables one to calc. the following bulk plasma properties as a function of the axial coordinate z: concn. of N2, H2, NH, NH2, NH3 mols. and N, H atoms in the ground electronic state; population in the electronically excited states N2(A3Σu+, B3πg, a'πu-, a1πg, C3πu, a''Σg+), H2(R) (an effective high Rydberg state) and N(2D,2P); concn. of the ions N2+, N2+(B), N4+, H2+, H3+, HN2+ and H-; vibrational level populations of N2(X1Σg+) and H2(X1Σg+) mols.; electron d. Ne, mean kinetic energy 3/2kTe, characteristic energy uk and drift velocity vd; discharge sustaining elec. field E; av. gas temp. across the tube T and wall temp. Tw. The calcns. are compared with data from different expts. in pure N2 and H2 discharges (measurements of elec. field as a function of current and pressure) and in N2-H2 discharges (measurements of relative changes in the elec. field and the N2(C), N2+(B) concns. as a function of the H2 percentage). From the comparison to expt., rate coeffs. for associative ionization upon collisions between two excited N2 mols. and deactivation of N2(a') and N2(X, v) by H atoms were estd. from the model.
- 13Tatarova, E.; Dias, F. M.; Gordiets, B.; Ferriera, C. M. Molecular Dissociation in N2-H2 Microwave Discharges Plasma Sources Sci. Technol. 2005, 14, 19– 31 DOI: 10.1088/0963-0252/14/1/003Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjtVKjsrk%253D&md5=6bda3e2fe3e3139b105975342f7da448Molecular dissociation in N2-H2 microwave dischargesTatarova, E.; Dias, F. M.; Gordiets, B.; Ferreira, C. M.Plasma Sources Science & Technology (2005), 14 (1), 19-31CODEN: PSTEEU; ISSN:0963-0252. (Institute of Physics Publishing)A microwave N2-H2 discharge driven by a traveling surface wave is investigated as a source of ground state N(4S) and H(1s) atoms. Exptl. investigations have been carried out in a plasma source operating at 2.45 GHz at low-pressure conditions (p = 0.5-2 torr). By means of optical emission spectroscopy and probe diagnostic techniques, the population densities of ground state atoms have been detected. The dissocn. kinetics is discussed in the framework of a theor. model based on a self-consistent treatment of the main discharge balances, wave electrodynamics and plasma-wall interactions. Electron-ion surface recombination processes involving HN+2 and N+2 ions are the most important sources of N(4S) gas phase atoms for the conditions considered. The relative no. of N(4S) atoms in respect to the total neutral d. remains approx. const. for percentages of H2 between 10% and 50% at nearly const. electron d. The competitive interplay of two important source channels of H(1s) atoms, namely electron impact dissocn. of H2 and H2 dissocn. via the quenching of nitrogen N2(a'1Σ-u) and N2 (A3 Σ+u) metastables, dets. a smooth decrease of hydrogen dissocn. when the amt. of hydrogen increases up to 50% in the mixt.
- 14van Helden, J. H.; Wagemans, W.; Yagci, G.; Zijlmans, R. A. B.; Schram, D. C.; Engeln, R.; Lombardi, G.; Stancu, G. D.; Röpcke, J. Detailed Studies of the Plasma-activated Catalytic Generation of Ammonia in N2-H2 Plasmas J. Appl. Phys. 2007, 101, 043305 DOI: 10.1063/1.2645828Google ScholarThere is no corresponding record for this reference.
- 15van Helden, J. H.; van den Oever, P. J.; Kessels, W. M. M.; van de Sanden, M. C. M.; Schram, D. C.; Engeln, R. Production Mechanisms of NH and NH2 Radicals in N2-H2 Plasmas J. Phys. Chem. A 2007, 111, 11460– 11472 DOI: 10.1021/jp0727650Google ScholarThere is no corresponding record for this reference.
- 16Ma, J.; Richley, J. C.; Ashfold, M. N. R.; Mankelevich, Yu.A. Probing the Plasma Chemistry in a Microwave Reactor used for Diamond Chemical Vapour Deposition by Cavity Ring Down Spectroscopy J. Appl. Phys. 2008, 104, 103305 DOI: 10.1063/1.3021095Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsVCktbvO&md5=817bef5ddba19c476d963ed666724743Probing the plasma chemistry in a microwave reactor used for diamond chemical vapor deposition by cavity ring down spectroscopyMa, Jie; Richley, James C.; Ashfold, Michael N. R.; Mankelevich, Yuri A.Journal of Applied Physics (2008), 104 (10), 103305/1-103305/9CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Abs. column densities of C2(a) and CH radicals and H(n = 2) atoms were measured in a diamond growing microwave reactor operating with hydrocarbon/Ar/H2 gas mixts. as functions of height (z) above the substrate surface and process conditions. The monitored species are each localized in the hot plasma region, where Tgas ∼ 3000 K, and their resp. column densities are each reproduced, quant., by 2-dimensional (r,z) modeling of the plasma chem. The H(n = 2) distribution is seen to peak nearer the substrate, reflecting its sensitivity both to thermal chem. (which drives the formation of ground state H atoms) and the distributions of electron d. (ne) and temp. (Te). All 3 column densities are sensitively dependent on the C/H ratio in the process gas mixt. but insensitive to the particular choice of hydrocarbon (CH4 and C2H2). The excellent agreement between measured and predicted column densities for all 3 probed species, under all process conditions studied, encourages confidence in the predicted no. densities of other of the more abundant radical species adjacent to the growing diamond surface which, in turn, reinforces the view that Me radicals are the dominant growth species in microwave activated hydrocarbon/Ar/H2 gas mixts. used in the CVD of microcryst. and single crystal diamond samples. (c) 2008 American Institute of Physics.
- 17Kelly, M. W.; Richley, J. C.; Western, C. M.; Ashfold, M. N. R.; Mankelevich, Yu. A. Exploring the Plasma Chemistry in Microwave Chemical Vapour Deposition of Diamond from C/H/O Gas Mixtures J. Phys. Chem. A 2012, 116, 9431– 9446 DOI: 10.1021/jp306190nGoogle ScholarThere is no corresponding record for this reference.
- 18Smith, J. A.; Wills, J. B.; Moores, H. S.; Orr-Ewing, A. J.; Ashfold, M. N. R.; Mankelevich, Yu.A.; Suetin, N. V. Effects of NH3 and N2 Additions to Hot Filament Activated CH4/H2 Gas Mixtures J. Appl. Phys. 2002, 92, 672– 681 DOI: 10.1063/1.1481961Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XkvFOqt78%253D&md5=548120ba8ad8d28cb569f98dcf6e2844Effects of NH3 and N2 additions to hot filament activated CH4/H2 gas mixturesSmith, James A.; Wills, Jonathan B.; Moores, Helen S.; Orr-Ewing, Andrew J.; Ashfold, Michael N. R.; Mankelevich, Yuri A.; Suetin, Nikolay V.Journal of Applied Physics (2002), 92 (2), 672-681CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Resonance enhanced multiphoton ionization and cavity ring down spectroscopies were used to provide spatially resolved measurements of relative H atom and CH3 radical no. densities, and NH column densities, in a hot filament (HF) reactor designed for diamond CVD and here operating with a 1% CH4/n/H2 gas mixt.-where n represents defined addns. of N2 or NH3. Three-dimensional modeling of the H/C/N chem. prevailing in such HF activated gas mixts. allows the relative no. d. measurements to be placed on an abs. scale. Expt. and theory both indicate that N2 is largely unreactive under the prevailing exptl. conditions, but NH3 addns. have a major effect on the gas phase chem. and compn. Specifically, NH3 addns. introduce an addnl. series of H-shift reactions NHx+H[rlhar2]NHx-1+H2 which gave N atoms with calcd. steady state no. densities >1013 cm-3 in the case of 1% NH3 addns. in the hotter regions of the reactor. These react, irreversibly, with C1 hydrocarbon species forming HCN products, thereby reducing the concn. of free hydrocarbon species (notably CH3) available to participate in diamond growth. The deduced redn. in CH3 no. d. due to competing gas phase chem. is compounded by NH3 induced modifications to the hot filament surface, which reduce its efficiency as a catalyst for H2 dissocn., thus lowering the steady state gas phase H atom concns. and the extent and efficiency of all subsequent gas phase transformations.
- 19Ma, J.; Ashfold, M. N. R.; Mankelevich, Yu. A. Validating Optical Emission Spectroscopy as a Diagnostic of Microwave Activated CH4/Ar/H2 Plasmas used for Diamond Chemical Vapor Deposition J. Appl. Phys. 2009, 105, 043302 DOI: 10.1063/1.3078032Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitlamurk%253D&md5=dadb1e77b273c4085bad7f56b31485b7Validating optical emission spectroscopy as a diagnostic of microwave activated CH4/Ar/H2 plasmas used for diamond chemical vapor depositionMa, Jie; Ashfold, Michael N. R.; Mankelevich, Yuri A.Journal of Applied Physics (2009), 105 (4), 043302/1-043302/12CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Spatially resolved optical emission spectroscopy (OES) was used to study the gas phase chem. and compn. in a microwave activated CH4/Ar/H2 plasma operating at moderate power densities (∼30 W cm-3) and pressures (≤175 torr) during CVD of polycryst. diamond. Several tracer species were monitored to gain information about the plasma. Relative concns. of ground state H (n = 1) atoms were detd. by actinometry, and the validity of this method were demonstrated for the present exptl. conditions. Electronically excited H (n = 3 and 4) atoms, Ar (4p) atoms, and C2 and CH radicals were studied also, by monitoring their emissions as functions of process parameters (Ar and CH4 flow rates, input power, and pressure) and of distance above the substrate. These various species exhibit distinctive behaviors, reflecting their different formation mechanisms. Relative trends identified by OES are in very good agreement with those revealed by complementary abs. absorption measurements (using cavity ring down spectroscopy) and with the results of complementary two-dimensional modeling of the plasma chem. prevailing within this reactor. (c) 2009 American Institute of Physics.
- 20Brazier, C. R.; Ram, R. S.; Bernath, P. F. Fourier Transform Spectroscopy of the A3Π–X3Σ– Transition of NH J. Mol. Spectrosc. 1986, 120, 381– 402 DOI: 10.1016/0022-2852(86)90012-3Google ScholarThere is no corresponding record for this reference.
- 21Fairchild, P. W.; Smith, G. P.; Crosley, D. R.; Jeffries, J. B. Lifetimes and Transition Probabilities for NH(A3Πi – X3Σ–) Chem. Phys. Lett. 1984, 107, 181– 186 DOI: 10.1016/0009-2614(84)85696-1Google ScholarThere is no corresponding record for this reference.
- 22Owono Owono, L. C.; Ben Abdallah, D.; Jaidane, N.; Ben Lakhdar, Z. Theoretical Radiative Properties Between States of the Triplet Manifold of NH Radical J. Chem. Phys. 2008, 128, 084309 DOI: 10.1063/1.2884923Google ScholarThere is no corresponding record for this reference.
- 23Western, C. M. PGOPHER, a Program for Simulating Rotational Structure; University of Bristol, http://pgopher.chm.bris.ac.uk.Google ScholarThere is no corresponding record for this reference.
- 24Roux, F.; Michaud, F.; Vervloet, M. High-Resolution Fourier Spectrometry of 14N2 Violet Emission Spectrum: Extensive Analysis of the C3Πu→B3Πg System J. Mol. Spectrosc. 1993, 158, 270– 277 DOI: 10.1006/jmsp.1993.1071Google ScholarThere is no corresponding record for this reference.
- 25Gilmore, F. R.; Laher, R. R.; Espy, P. J. Franck-Condon Factors, r-Centroids, Electronic Transition Moments, and Einstein Coefficients for Many Nitrogen and Oxygen Band Systems J. Phys. Chem. Ref. Data 1992, 21, 1005– 1107 DOI: 10.1063/1.555910Google ScholarThere is no corresponding record for this reference.
- 26Plemmons, D. H.; Parigger, C.; Lewis, J. W. L.; Hornkohl, J. O. Analysis of Combined Spectra of NH and N2 Appl. Opt. 1998, 37, 2493– 2498 DOI: 10.1364/AO.37.002493Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXivVSlsrY%253D&md5=42a042405abc9ea0e837f987af1e6f18Analysis of combined spectra of NH and N2Plemmons, David H.; Parigger, Christian; Lewis, James W. L.; Hornkohl, James O.Applied Optics (1998), 37 (12), 2493-2498CODEN: APOPAI; ISSN:0003-6935. (Optical Society of America)Gas phase diagnostics with multispecies diat. spectra is discussed. Analyses of spectra from the A3Πi ↔ X3Σ- system of NH and the C3Πu ↔ B3Πg 2nd-pos. system of N2 are presented. Multispecies spectroscopy is applied to exptl. spectra obtained from laser-induced breakdown plasmas in anhyd. NH3 gas and a low-pressure discharge lamp.
- 27Kramida, A.; Ralchenko, Yu.; Reader, J.; NIST ASD Team. NIST Atomic Spectra Database (version 5.2), [Online]; National Institute of Standards and Technology: Gaithersburg, MD, 2014; available athttp://physics.nist.gov/asd (Tuesday, 28-Apr-2015 04:49:32 EDT).Google ScholarThere is no corresponding record for this reference.
- 28Moore, C. E.Selected Tables of Atomic Spectra, Atomic Energy Levels and Multiplet Tables–N I, N II, N III; National Standard Reference Data Series (United States National Bureau of Standards); 1975, document 3, section 5.Google ScholarThere is no corresponding record for this reference.
- 29Tachiev, G. I.; Froese Fischer, C. Breit-Pauli Energy Levels and Transition Rates for Nitrogen-like and Oxygen-like Sequences Astron. Astrophys. 2002, 385, 716– 723 DOI: 10.1051/0004-6361:20011816Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XktV2lur4%253D&md5=8a829749533395b1dc6b19897f731101Breit-Pauli energy levels and transition rates for nitrogen-like and oxygen-like sequencesTachiev, G. I.; Fischer, C. FroeseAstronomy and Astrophysics (2002), 385 (2), 716-723CODEN: AAEJAF; ISSN:0004-6361. (EDP Sciences)Breit-Pauli results for energy levels, lifetimes, and Lande gJ factors were detd. for all levels up to 2p23d of the N-like sequence (Z = 7-17) and 2p33d of the O-like sequence (Z = 8-20). Exceptions are some lower members of the sequence where the spectrum included only those levels below the second 2p24s term in the case of N-like or 2p34s in the case of O-like. The computed energy and E1, E2, M1, M2 transition data between all levels, including convergence of the LS line strength for both length and velocity forms, may be viewed at a website. Critically evaluated transition data is presented for N I, O II, Mg VI, and Si VIII (N-like sequence) and O I, Ne III, Mg V, and Si VII (O-like) for E1 transitions including uncertainty ests. The accuracy of energy levels is detd. by comparison with expt. Transition rates with uncertainties are compared with expt. and other theory.
- 30
An assumption that the kinetics of the N(2p23p1) states with energies ≈12 eV (i.e., excitation by EI balanced by radiative decay) resemble those of H(n = 3) allows the following order-of-magnitude estimate of the N(2p23p1) concentration under base conditions: [N(2p23p1)] ∼ [N(2p3)] × [H(n = 3)]/[H(n = 1)] ≈ 200 cm–3 given typical calculated values for the [H(n = 3)]/[H(n = 1)] ratio (≈2 × 10–10) and the concentration of ground state nitrogen atoms ([N(2p3)] < 1012 cm–3) in the plasma core (see section 4).
There is no corresponding record for this reference. - 31Ma, J.; Richley, J. C.; Davies, D. R. W.; Cheesman, A.; Ashfold, M. N. R.; Mankelevich, Yu. A. Spectroscopic and Modelling Investigations of the Gas Phase Chemistry and Composition in Microwave Plasma Activated B2H6/Ar/H2 Gas Mixtures J. Phys. Chem. A 2010, 114, 2447– 2463 DOI: 10.1021/jp9094694Google ScholarThere is no corresponding record for this reference.
- 32Smith, G. P.; Golden, D. M.; Frenklach, M.; Moriarty, N. W.; Eiteneer, B.; Goldenberg, M.; Bowman, C. T.; Hanson, R. K.; Song, S.; Gardiner, W. C.; GRI-Mech 3.0; http://www.me.berkeley.edu/gri_mech/.Google ScholarThere is no corresponding record for this reference.
- 33Davidson, D. F.; Kohse-Hoinghaus, K.; Chang, A. Y.; Hanson, R. K. A Pyrolysis Mechanism for Ammonia Int. J. Chem. Kinet. 1990, 22, 513– 535 DOI: 10.1002/kin.550220508Google Scholar33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXksVOgsLg%253D&md5=078292afae6b8d9b33aef497d834b7ffA pyrolysis mechanism for ammoniaDavidson, D. F.; Kohse-Hoeinghaus, K.; Chang, A. Y.; Hanson, R. K.International Journal of Chemical Kinetics (1990), 22 (5), 513-35CODEN: IJCKBO; ISSN:0538-8066.The mechanism of NH3 pyrolysis was investigated over a wide range of conditions behind reflected shock waves. Quant. time-history measurements of the species NH and NH2 were made by using narrow-linewidth laser absorption. Rate coeffs. for several reactions which influence the NH and NH2 profiles were fitted in the temp. range 2200-2800 K. The reaction and the corresponding best fit rate coeffs. are as follows: NH2 + H → NH + H2 with a rate coeff. of 4.0 × 1013 exp(-3650/RT) cm3 mol-1 s-1, NH2 + NH → N2H2 + H with a rate coeff. of 1.5 × 1015T-0.5 cm3 mol-3 s-1. The temp. dependences of these rate coeffs. are based on previous ests. The exptl. data from 4 earlier measurements of the dissocn. reaction NH3 + M → NH2 + H + M were reanalyzed in light of recent data for the rate of NH3 + H → NH2 + H2, and an improved rate coeff. of 2.2 × 1016 exp(-93470/RT) cm3 mol-1 s-1 as 1740-3300 K was obtained.
- 34Dean, A. M.; Bozzelli, J. W. Combustion Chemistry of Nitrogen. In Gas Phase Combustion Chemistry; Gardiner, W. C., Ed.; Springer-Verlag: New York, 2000; Chapter 2.Google ScholarThere is no corresponding record for this reference.
- 35Millar, T. J.; Farquhar, P. R. A.; Willacy, P. K. The UMIST Database for Astrochemistry 1995 Astron. Astrophys., Suppl. Ser. 1997, 121, 139– 185 DOI: 10.1051/aas:1997118Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXhtVCjtb0%253D&md5=4b62600063c77bafb7c8cc4956688f63The UMIST database for astrochemistry 1995Millar, T.J.; Farquhar, P.R.A.; Willacy, K.Astronomy & Astrophysics, Supplement Series (1997), 121 (1), 139-185CODEN: AAESB9; ISSN:0365-0138. (Editions de Physique)We report the release of a new version of the UMIST database for astrochem. The database contains the rate coeffs. of 3864 gas-phase reactions important in interstellar and circumstellar chem. and involves 395 species and 12 elements. The previous (1990) version of this database has been widely used by modellers. In addn. to the rate coeffs., we also tabulate permanent elec. dipole moments of the neutral species and heats of formation. A numerical model of the chem. evolution of a dark cloud is calcd. and important differences to that calcd. with the previous database noted.
- 36Richley, J. C.; Fox, O. J. L.; Ashfold, M. N. R.; Mankelevich, Yu. A. Combined Experimental and Modelling Studies of Microwave Activated CH4/H2/Ar Plasmas for Microcrystalline, Nanocrystalline, and Ultrananocrystalline Diamond Deposition J. Appl. Phys. 2011, 109, 063307 DOI: 10.1063/1.3562185Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjvVWkurw%253D&md5=5c718c66e390e582efc8c32363ae8c38Combined experimental and modeling studies of microwave activated CH4/H2/Ar plasmas for microcrystalline, nanocrystalline, and ultrananocrystalline diamond depositionRichley, James C.; Fox, Oliver J. L.; Ashfold, Michael N. R.; Mankelevich, Yuri A.Journal of Applied Physics (2011), 109 (6), 063307/1-063307/14CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)A comprehensive study of microwave (MW) activated CH4/H2/Ar plasmas used for diamond CVD is reported, focusing particularly on the effects of gross variations in the H2/Ar ratio in the input gas mixt. (from H2/Ar mole fraction ratios of > 10:1, through to ∼1:99). Abs. column densities of C2(a) and CH(X) radicals and of H(n = 2) atoms were detd. by cavity ringdown spectroscopy, as functions of height (z) above a substrate and of process conditions (CH4, H2, and Ar input mole fractions, total pressure, p, and input microwave power, P). Optical emission spectroscopy was also used to explore the relative densities of electronically excited H atoms, and CH, C2, and C3 radicals, as functions of these same process conditions. These exptl. data are complemented by extensive 2D (r, z) modeling of the plasma chem., which provides a quant. rationale for all of the exptl. observations. Progressive replacement of H2 by Ar (at const. p and P) leads to an expanded plasma vol. Under H2-rich conditions, > 90% of the input MW power is absorbed through rovibrational excitation of H2. Reducing the H2 content (as in an Ar-rich plasma) leads to a redn. in the absorbed power d.; the plasma necessarily expands to accommodate a given input power. The av. power d. in an Ar-rich plasma is much lower than that in an H2-rich plasma operating at the same p and P. Progressive replacement of H2 by Ar is shown also to result in an increased electron temp., an increased H/H2 no. d. ratio, but little change in the max. gas temp. in the plasma core (which is consistently ∼3000 K). Given the increased H/H2 ratio, the fast H-shifting (CyHx + H ↔ CyHx-1 + H2; y = 1-3) reactions ensure that the core of Ar-rich plasma contains much higher relative abundances of "product" species like C atoms, and C2, and C3 radicals. The effects of Ar diln. on the absorbed power dissipation pathways and the various species concns. just above the growing diamond film are also investigated and discussed. (c) 2011 American Institute of Physics.
- 37Guerra, V.; Sa, P. A.; Loureiro, J. Kinetic Modelling of Low-Pressure Nitrogen Discharges and Post-Discharges Eur. Phys. J.: Appl. Phys. 2004, 28, 125– 152 DOI: 10.1051/epjap:2004188Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvFOrug%253D%253D&md5=ec12ecef6296eb5052cc7d398dc234f2Kinetic modeling of low-pressure nitrogen discharges and post-dischargesGuerra, V.; Sa, P. A.; Loureiro, J.European Physical Journal: Applied Physics (2004), 28 (2), 125-152CODEN: EPAPFV; ISSN:1286-0042. (EDP Sciences)A review. The kinetic modeling of low-pressure (p ∼ 1-10 torr) stationary nitrogen discharges and the corresponding afterglows is reviewed. It is shown that a good description of the overall behavior of nitrogen plasmas requires a deep understanding of the coupling between different kinetics. The central role is played by ground-state vibrationally excited mols., N2(X 1Σ+g, ν), which have a strong influence on the shape of the electron energy distribution function, on the creation and destruction of electronically excited states, on the gas heating, dissocn. and on afterglow emissions. N2(X 1Σ+g, ν) mols. are actually the hinge ensuring a strong link between the various kinetics. The noticeable task done by electronically excited metastable mols., in particular N2(A 3Σ+u) and N2(α' Σ-u), is also pointed out. Besides contributing to the same phenomena as vibrationally excited mols., these electronic metastable states play also a categorical role in ionization. Furthermore, vibrationally excited mols. in high ν levels are in the origin of the peaks obsd. in the flowing afterglow for the concns. of several species, such as N2(A 3Σ+g), N2(B 3Πg), N2+(B 2Σ-u) and electrons, which occur downstream from the discharge after a dark zone as a consequence of the V-V pumping-up mechanism.
- 38Hack, W.; Kurzke, H.; Ottinger, Ch.; Wagner, H. Gg. Elementary Reactions of Electronically Excited N2 in the 3Σ+u State with H2 and NH3 Chem. Phys. 1988, 126, 111– 124 DOI: 10.1016/0301-0104(88)85024-9Google ScholarThere is no corresponding record for this reference.
- 39Herron, J. T. Evaluated Chemical Kinetics Data for Reactions of N(2D), N(2P) and N2(A3Σ+u) in the Gas Phase J. Phys. Chem. Ref. Data 1999, 28, 1453– 1483DOI: 10.1063/1.556043
and references therein
Google ScholarThere is no corresponding record for this reference. - 40Slanger, T. G.; Wood, B. J.; Black, G. Temperature Dependent N2(A3Σ+u) Quenching Rate Coefficients J. Photochem. 1973, 2, 63– 66 DOI: 10.1016/0047-2670(73)80005-XGoogle Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE3sXlt1Sjur0%253D&md5=89fec63e53394d67761de20396eb92baTemperature-dependent molecular nitrogen (A3 σ+u) quenching rate coefficientsSlanger, T. G.; Wood, B. J.; Black, G.Journal of Photochemistry (1973), 2 (1), 63-6CODEN: JPCMAE; ISSN:0047-2670.The reactions of N2(A3Σ+u) with 6 different quenching gases (N2O, O2, CO, C2H6, CH4, and H2) are studied at various temps. N2 (A) mols. are produced by photolysis of N2O at 1470 Å. N2 (A) mols. are detected by chemiluminescence (NO (γ)-bend signal) following NO addn. The rate coeffs. at different temps., the activation energy, and the log of the preexponential factor are calcd. and discussed. The rate coeffs. at 300°K are compared with those of Callear and Wood (1971) and Setser, et al. (1971). Agreement is good for those species that have quenching coeffs. faster than 5 × 1011 cm3/mol.-sec.
- 41Pancheshnyi, S. V.; Starikovskaia, S. M.; Starikovskii, A. Yu. Collisional Deactivation of N2(C3Πu, v = 0, 1, 2, 3) States by N2, O2, H2 and H2O Molecules Chem. Phys. 2000, 262, 349– 357 DOI: 10.1016/S0301-0104(00)00338-4Google ScholarThere is no corresponding record for this reference.
- 42Adam, L.; Hack, W.; Zhu, H.; Qu, Z.-W.; Schinke, R. Experimental and Theoretical Investigation of the Reaction NH(X3Σ–) + H(2S) → N(4S) + H2(X1S+g) J. Chem. Phys. 2005, 122, 114301 DOI: 10.1063/1.1862615Google ScholarThere is no corresponding record for this reference.
- 43Ho, G. H.; Golde, M. F. Experimental Study of the Reactions of N2(A3Σ+u) with H Atoms and OH Radicals J. Chem. Phys. 1991, 95, 8866– 8870 DOI: 10.1063/1.461219Google ScholarThere is no corresponding record for this reference.
Cited By
This article is cited by 30 publications.
- Nitu Syed, Alastair Stacey, Ali Zavabeti, Chung Kim Nguyen, Benedikt Haas, Christoph T. Koch, Daniel L. Creedon, Enrico Della Gaspera, Philipp Reineck, Azmira Jannat, Matthias Wurdack, Sarah E. Bamford, Paul J. Pigram, Sherif Abdulkader Tawfik, Salvy P. Russo, Billy J. Murdoch, Kourosh Kalantar-Zadeh, Chris F. McConville, Torben Daeneke. Large Area Ultrathin InN and Tin Doped InN Nanosheets Featuring 2D Electron Gases. ACS Nano 2022, 16
(4)
, 5476-5486. https://doi.org/10.1021/acsnano.1c09636
- Edward J. D. Mahoney, Alim K. S. K. Lalji, John W. R. Allden, Benjamin S. Truscott, Michael N. R. Ashfold, Yuri A. Mankelevich. Optical Emission Imaging and Modeling Investigations of Microwave-Activated SiH4/H2 and SiH4/CH4/H2 Plasmas. The Journal of Physical Chemistry A 2020, 124
(25)
, 5109-5128. https://doi.org/10.1021/acs.jpca.0c03396
- Michael N. R. Ashfold, Jonathan P. Goss, Ben L. Green, Paul W. May, Mark E. Newton, Chloe V. Peaker. Nitrogen in Diamond. Chemical Reviews 2020, 120
(12)
, 5745-5794. https://doi.org/10.1021/acs.chemrev.9b00518
- Qianqian Chen, Alp Ozkan, Basab Chattopadhyay, Kitty Baert, Claude Poleunis, Alisson Tromont, Rony Snyders, Arnaud Delcorte, Herman Terryn, Marie-Paule Delplancke-Ogletree, Yves H. Geerts, François Reniers. N-Doped TiO2 Photocatalyst Coatings Synthesized by a Cold Atmospheric Plasma. Langmuir 2019, 35
(22)
, 7161-7168. https://doi.org/10.1021/acs.langmuir.9b00784
- Edward
J. D. Mahoney, Benjamin S. Truscott, Sohail Mushtaq, Michael N. R. Ashfold, Yuri A. Mankelevich. Spatially Resolved Optical Emission and Modeling Studies of Microwave-Activated Hydrogen Plasmas Operating under Conditions Relevant for Diamond Chemical Vapor Deposition. The Journal of Physical Chemistry A 2018, 122
(42)
, 8286-8300. https://doi.org/10.1021/acs.jpca.8b07491
- E. J. D. Mahoney, B. S. Truscott, M. N. R. Ashfold, and Yu. A. Mankelevich . Optical Emission from C2– Anions in Microwave-Activated CH4/H2 Plasmas for Chemical Vapor Deposition of Diamond. The Journal of Physical Chemistry A 2017, 121
(14)
, 2760-2772. https://doi.org/10.1021/acs.jpca.7b00814
- Benjamin S. Truscott, Mark W. Kelly, Katie J. Potter, and Michael N. R. Ashfold , Yuri A. Mankelevich . Microwave Plasma-Activated Chemical Vapor Deposition of Nitrogen-Doped Diamond. II: CH4/N2/H2 Plasmas. The Journal of Physical Chemistry A 2016, 120
(43)
, 8537-8549. https://doi.org/10.1021/acs.jpca.6b09009
- Artem Martyanov, Ivan Tiazhelov, Valery Voronov, Sergey Savin, Alexey Popovich, Victor Ralchenko, Vadim Sedov. Nitrogen‐Induced Microcrystalline‐to‐Nanocrystalline Structure Transition in Diamond Films Grown by Microwave Plasma Chemical Vapor Deposition: Comparison of N
2
and NH
3
Precursors. physica status solidi (a) 2024, 142 https://doi.org/10.1002/pssa.202400372
- A. K. Martyanov, I. A. Tyazhelov, A. F. Popovich, V. G. Ralchenko, S. S. Savin, V. S. Sedov. Comparison оf Secondary Nucleation Processes during Diamond Synthesis in Microwave Plasma in H2–CH4–N2 and H2–CH4–NH3 Gas Mixtures. Bulletin of the Lebedev Physics Institute 2024, 51
(6)
, 195-201. https://doi.org/10.3103/S106833562460044X
- Michael N.R. Ashfold, Yuri A. Mankelevich. Two-dimensional modeling of diamond growth by microwave plasma activated chemical vapor deposition: Effects of pressure, absorbed power and the beneficial role of nitrogen on diamond growth. Diamond and Related Materials 2023, 137 , 110097. https://doi.org/10.1016/j.diamond.2023.110097
- Alexander A. Konnov. An exploratory modelling study of chemiluminescence in ammonia-fuelled flames. Part 1. Combustion and Flame 2023, 253 , 112788. https://doi.org/10.1016/j.combustflame.2023.112788
- Quoc Hue Pho, LiangLiang Lin, Evgeny V. Rebrov, Mohammad Mohsen Sarafraz, Thanh Tung Tran, Nam Nghiep Tran, Dusan Losic, Volker Hessel. Process intensification for gram-scale synthesis of N-doped carbon quantum dots immersing a microplasma jet in a gas-liquid reactor. Chemical Engineering Journal 2023, 452 , 139164. https://doi.org/10.1016/j.cej.2022.139164
- Weikang Zhao, Yan Teng, Kun Tang, Shunming Zhu, Kai Yang, Jingjing Duan, Yingmeng Huang, Ziang Chen, Jiandong Ye, Shulin Gu. Significant suppression of residual nitrogen incorporation in diamond film with a novel susceptor geometry employed in MPCVD. Chinese Physics B 2022, 31
(11)
, 118102. https://doi.org/10.1088/1674-1056/ac7298
- Jin Liu, Xinbo Zhu, Xueli Hu, Fei Zhang, Xin Tu. Plasma-assisted ammonia synthesis in a packed-bed dielectric barrier discharge reactor: effect of argon addition. Vacuum 2022, 197 , 110786. https://doi.org/10.1016/j.vacuum.2021.110786
- Michael N R Ashfold, Yuri A Mankelevich. Self-consistent modeling of microwave activated N
2
/CH
4
/H
2
(and N
2
/H
2
) plasmas relevant to diamond chemical vapor deposition. Plasma Sources Science and Technology 2022, 31
(3)
, 035005. https://doi.org/10.1088/1361-6595/ac409e
- Ryuta Ichiki, Noritake Yagawa, Takashi Furuki, Seiji Kanazawa. Extension of Treatable Area in Atmospheric-Pressure Plasma-Jet Nitriding. Tetsu-to-Hagane 2022, 108
(6)
, 354-359. https://doi.org/10.2355/tetsutohagane.TETSU-2021-124
- Chang-Hua Yu, Kun-An Chiu, Thi-Hien Do, Li Chang, Wei-Chun Chen. Formation of Aligned α-Si3N4 Microfibers by Plasma Nitridation of Si (110) Substrate Coated with SiO2. Coatings 2021, 11
(10)
, 1251. https://doi.org/10.3390/coatings11101251
- Ahmadreza Amini, Mohammad Latifi, Jamal Chaouki. Electrification of materials processing via microwave irradiation: A review of mechanism and applications. Applied Thermal Engineering 2021, 193 , 117003. https://doi.org/10.1016/j.applthermaleng.2021.117003
- Andrew M Edmonds, Connor A Hart, Matthew J Turner, Pierre-Olivier Colard, Jennifer M Schloss, Kevin S Olsson, Raisa Trubko, Matthew L Markham, Adam Rathmill, Ben Horne-Smith, Wilbur Lew, Arul Manickam, Scott Bruce, Peter G Kaup, Jon C Russo, Michael J DiMario, Joseph T South, Jay T Hansen, Daniel J Twitchen, Ronald L Walsworth. Characterisation of CVD diamond with high concentrations of nitrogen for magnetic-field sensing applications. Materials for Quantum Technology 2021, 1
(2)
, 025001. https://doi.org/10.1088/2633-4356/abd88a
- Andre Ricard, Yunfei Wang, Yoon Sang Lee, Jean-Philippe Sarrette, Ansoon Kim, Yu Kwon Kim. Controlling N and C-atom densities in N2/H2 and N2/CH4 microwave afterglows for selective TiO2 surface nitriding. Applied Surface Science 2021, 540 , 148348. https://doi.org/10.1016/j.apsusc.2020.148348
- Aparna Das, Bimal Krishna Banik. Microwave-assisted CVD processes for diamond synthesis. 2021, 329-374. https://doi.org/10.1016/B978-0-12-822895-1.00004-7
- Sergio Conejeros, M. Zamir Othman, Alex Croot, Judy N. Hart, Kane M. O’Donnell, Paul W. May, Neil L. Allan. Hunting the elusive shallow n-type donor – An ab initio study of Li and N co-doped diamond. Carbon 2021, 171 , 857-868. https://doi.org/10.1016/j.carbon.2020.09.065
- Robert Peverall, Grant A D Ritchie. Spectroscopy techniques and the measurement of molecular radical densities in atmospheric pressure plasmas. Plasma Sources Science and Technology 2019, 28
(7)
, 073002. https://doi.org/10.1088/1361-6595/ab2956
- John Mantzaras. Progress in non-intrusive laser-based measurements of gas-phase thermoscalars and supporting modeling near catalytic interfaces. Progress in Energy and Combustion Science 2019, 70 , 169-211. https://doi.org/10.1016/j.pecs.2018.10.005
- R Perillo, R Chandra, G R A Akkermans, W A J Vijvers, W A A D Graef, I G J Classen, J van Dijk, M R de Baar. Studying the influence of nitrogen seeding in a detached-like hydrogen plasma by means of numerical simulations. Plasma Physics and Controlled Fusion 2018, 60
(10)
, 105004. https://doi.org/10.1088/1361-6587/aad703
- A. Tallaire, L. Mayer, O. Brinza, M. A. Pinault-Thaury, T. Debuisschert, J. Achard. Highly photostable NV centre ensembles in CVD diamond produced by using N2O as the doping gas. Applied Physics Letters 2017, 111
(14)
https://doi.org/10.1063/1.5004106
- K. V. Mironovich, Yu. A. Mankelevich, D. G. Voloshin, S. A. Dagesyan, V. A. Krivchenko. Simulation and optical spectroscopy of a DC discharge in a CH4/H2/N2 mixture during deposition of nanostructured carbon films. Plasma Physics Reports 2017, 43
(8)
, 844-857. https://doi.org/10.1134/S1063780X17080098
- C.J. Tang, Haihong Hou, A.J.S. Fernandes, X.F. Jiang, J.L. Pinto, H. Ye. Investigation of bonded hydrogen defects in nanocrystalline diamond films grown with nitrogen/methane/hydrogen plasma at high power conditions. Journal of Crystal Growth 2017, 460 , 16-22. https://doi.org/10.1016/j.jcrysgro.2016.12.050
- Jan Voráč, Petr Synek, Lucia Potočňáková, Jaroslav Hnilica, Vít Kudrle. Batch processing of overlapping molecular spectra as a tool for spatio-temporal diagnostics of power modulated microwave plasma jet. Plasma Sources Science and Technology 2017, 26
(2)
, 025010. https://doi.org/10.1088/1361-6595/aa51f0
- Michael N. R. Ashfold, Edward J. D. Mahoney, Sohail Mushtaq, Benjamin S. Truscott, Yuri A. Mankelevich. What [plasma used for growing] diamond can shine like flame?. Chemical Communications 2017, 53
(76)
, 10482-10495. https://doi.org/10.1039/C7CC05568D
Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.
Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.
The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.
Recommended Articles
References
This article references 43 other publications.
- 1Breeding, C. M.; Shigley, J. E. The ‘Type’ Classification System of Diamonds and its Importance in Gemology Gems Gemol. 2009, 45, 96– 111 DOI: 10.5741/GEMS.45.2.961https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXpvF2ns7g%253D&md5=e2a02c3b8cab00e67566513f8e384d6fThe "type" classification system of diamonds and its importance in gemologyBreeding, Christopher M.; Shigley, James E.Gems and Gemology (2009), 45 (2), 96-111CODEN: GEGEA2; ISSN:0016-626X. (Gemological Institute of America)A review. Diamond "type" is a concept that is frequently mentioned in the gemol. literature, but its relevance to the practicing gemologist is rarely discussed. Diamonds are broadly divided into two types (I and II) based on the presence or absence of nitrogen impurities, and further subdivided according to the arrangement of nitrogen atoms (isolated or aggregated) and the occurrence of boron impurities. Diamond type is directly related to color and the lattice defects that are modified by treatments to change color. Knowledge of type allows gemologists to better evaluate if a diamond might be treated or synthetic, and whether it should be sent to a lab. for testing. Scientists det. type using expensive FTIR instruments, but many simple gemol. tools (e.g., a microscope, spectroscope, UV lamp) can give strong indications of diamond type.
- 2Tallaire, A.; Collins, A. T.; Charles, D.; Achard, J.; Sussmann, R.; Gicquel, A.; Newton, M. E.; Edmonds, A. M.; Cruddace, R. J. Characterisation of High-quality Thick Single-crystal Diamond Grown by CVD with Low Nitrogen Content Diamond Relat. Mater. 2006, 15, 1700– 1707 DOI: 10.1016/j.diamond.2006.02.0052https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVSisLfO&md5=9d733985730097daf389f8359d6a1750Characterisation of high-quality thick single-crystal diamond grown by CVD with a low nitrogen additionTallaire, A.; Collins, A. T.; Charles, D.; Achard, J.; Sussmann, R.; Gicquel, A.; Newton, M. E.; Edmonds, A. M.; Cruddace, R. J.Diamond and Related Materials (2006), 15 (10), 1700-1707CODEN: DRMTE3; ISSN:0925-9635. (Elsevier B.V.)Single-crystal homoepitaxial diamond was grown by CVD using a high-d. microwave plasma. The growth rate can be increased by factors of ≤2.5 by adding small concns. (2-10 ppm) of N to the gas phase. Free-standing specimens ≤1.7 mm thick were characterized using optical absorption, cathodoluminescence, photoluminescence, and Raman spectroscopies, and by ESR. These techniques all demonstrate that the colorless type IIa material is of excellent quality with total defect concns. not exceeding 200 ppb, and is ideally suited for optical and electronic applications.
- 3Chayahara, A.; Mokuno, Y.; Horino, Y.; Takasu, Y.; Kato, H.; Yoshikawa, H.; Fujimori, N. The Effect of Nitrogen Addition during High-rate Homoepitaxial Growth of Diamond by Microwave Plasma CVD Diamond Relat. Mater. 2004, 13, 1954– 1958 DOI: 10.1016/j.diamond.2004.07.0073https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXpt1WlsLk%253D&md5=6e9c894e0a185e89c59012e1ac8885ecThe effect of nitrogen addition during high-rate homoepitaxial growth of diamond by microwave plasma CVDChayahara, A.; Mokuno, Y.; Horino, Y.; Takasu, Y.; Kato, H.; Yoshikawa, H.; Fujimori, N.Diamond and Related Materials (2004), 13 (11-12), 1954-1958CODEN: DRMTE3; ISSN:0925-9635. (Elsevier B.V.)The effect of nitrogen addn. on growth rate, morphol. and crystallinity during high-rate microwave plasma chem. vapor deposition (MPCVD) of diamond was investigated. Epitaxial diamond was grown on type Ib diamond (100) substrates using a 5-kW, 2.45-GHz microwave plasma CVD system with nitrogen addn. in the methane and hydrogen source gases. In order to obtain high growth rates, we designed the substrate holders to generate high-d. plasma. The growth rates ranged from 30 to 120 μm/h. The nitrogen addn. enhanced the growth rate by a factor of 2 and was beneficial to create a macroscopic smooth (100) face avoiding the growth of hillocks. However, the (100) surfaces looked microscopically rough by bunched steps as the effect of nitrogen addn. The macroscopic smoothing during the growth enabled the long-term stable deposition required to obtain large crystals. The deposited diamond was characterized by optical microscope, Raman spectroscopy, cathodoluminescence spectroscopy and X-ray diffraction.
- 4Lu, J.; Gu, Y.; Grotjohn, T. A.; Schuelke, T.; Asmussen, J. Experimentally Defining the Safe and Efficient, High Pressure Microwave Plasma Assisted CVD Operating Regime for Single Crystal Diamond Synthesis Diamond Relat. Mater. 2013, 37, 17– 28 DOI: 10.1016/j.diamond.2013.04.0074https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXpvVeqtrc%253D&md5=56f2193c7248d0621e007c997628a229Experimentally defining the safe and efficient, high pressure microwave plasma assisted CVD operating regime for single crystal diamond synthesisLu, J.; Gu, Y.; Grotjohn, T. A.; Schuelke, T.; Asmussen, J.Diamond and Related Materials (2013), 37 (), 17-28CODEN: DRMTE3; ISSN:0925-9635. (Elsevier B.V.)The detailed exptl. behavior of a microwave plasma assisted CVD (MPACVD) reactor operating within the high, 180-300 torr, pressure regime is presented. An exptl. methodol. is described that 1st defines the reactor operating field map and then enables, while operating at these high pressures, the detn. of the efficient, safe and discharge stable diamond synthesis process window. Within this operating window discharge absorbed power densities of 300-1000 W/cm3 are achieved and high quality, single crystal diamond (SCD) synthesis rates of 20-75 μm/h are demonstrated. The influence of several input exptl. variables including pressure, N2 concn., CH4 percentage and substrate temp. on SCD deposition is explored. At a const. pressure of 240 torr, a high quality, high growth rate SCD synthesis window vs. substrate temp. is exptl. identified between 1030 and 1250°. When the input N impurity level is reduced <10 ppm in the gas phase the quality of the synthesized diamond is IIa or better.
- 5Bogdanov, S.; Vikharev, A.; Gorbachev, A.; Muchnikov, A.; Radishev, D.; Ovechkin, N.; Parshin, V. Growth-rate Enhancement of High-quality, Low-loss CVD-produced Diamond Disks Grown for Microwave Windows Application Chem. Vap. Deposition 2014, 20, 32– 38 DOI: 10.1002/cvde.2013070585https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjslWku74%253D&md5=e06b2e9df3cb7f20175d28bbffe7daf3Growth-rate Enhancement of High-quality, Low-loss CVD-produced Diamond Disks Grown for Microwave Windows ApplicationBogdanov, Sergey; Vikharev, Anatoly; Gorbachev, Aleksei; Muchnikov, Anatoly; Radishev, Dmitry; Ovechkin, Nikolai; Parshin, VladimirChemical Vapor Deposition (2014), 20 (1-2-3), 32-38CODEN: CVDEFX; ISSN:0948-1907. (Wiley-Blackwell)The effect of nitrogen addn. on the growth rate, quality, and properties of polycryst. diamond grown by microwave plasma assisted (MPA)CVD is investigated. Two series of expts. are performed at two different microwave power densities (40 and 110 W cm-3) using a 2.45 GHz cylindrical microwave reactor. The results show that the beneficial effect of nitrogen is more distinct at higher microwave power densities. To investigate the properties of polycryst. diamond grown with nitrogen addn., a thick diamond disk of 50 mm diam. is grown with an addn. of 50 ppm nitrogen using a 2.45 GHz ellipsoidal microwave reactor. The grown diamond disk has a thermal cond. of 17.3 W cm-1 K-1 and dielec. loss tangent of 3.7 × 10-5 at a frequency of 170 GHz, and its parameters are suitable for application in microwave windows (e.g., gyrotron windows). Our results indicate that it is possible to achieve the increased (by a factor of 2.5) growth rates by nitrogen addn. without significant degrdn. of diamond quality, and properties such as thermal cond. and dielec. loss tangent.
- 6Achard, J.; Silva, F.; Brinza, O.; Tallaire, A.; Gicquel, A. Coupled Effect of Nitrogen Addition and Surface Temperature on the Morphology and the Kinetics of Thick CVD Diamond Single Crystals Diamond Relat. Mater. 2007, 16, 685– 689 DOI: 10.1016/j.diamond.2006.09.0126https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXkt1alt7w%253D&md5=4c1dd701816ab0a9ae2d7cb01047c9cbCoupled effect of nitrogen addition and surface temperature on the morphology and the kinetics of thick CVD diamond single crystalsAchard, J.; Silva, F.; Brinza, O.; Tallaire, A.; Gicquel, A.Diamond and Related Materials (2007), 16 (4-7), 685-689CODEN: DRMTE3; ISSN:0925-9635. (Elsevier B.V.)In this study, homoepitaxial thick diamond films were grown by CVD at high microwave power densities for temps. ranging from 800° to 950° and with nitrogen addns. from 75 to 200 ppm relative to the total gas flow. There is a coupled effect of these two parameters on the growth mechanisms of the CVD diamond film. For a deposition temp. close to 875° and for the lowest nitrogen concn., the growth proceeded via a step flow mode identified by classical step bunching phenomena due to the presence of nitrogen and leading to the appearance of macro-steps. When nitrogen concn. was increased keeping the same temp., the growth mode evolved from a step flow mode to a bidimensional nucleation mode, for which macro-steps are no longer obsd. For higher growth temps. (950°), this growth mode transition still exists but appears for much higher nitrogen concn. These different observations, assocd. with the resulting growth rates, are discussed in terms of surface modification induced by the presence of nitrogen impurity. It is shown in particular that an increase of nitrogen concn. is equiv. to an increase of the surface supersatn., this effect being compensated by an increase of the deposition temp.
- 7Vandevelde, T.; Wu, T. D.; Quaeyhaegens, C.; Vlekken, J.; D’Olieslaeger, M.; Stals, L. Correlation Between the OES Plasma Composition and the Diamond Film Properties during Microwave PA-CVD with Nitrogen Addition Thin Solid Films 1999, 340, 159– 163 DOI: 10.1016/S0040-6090(98)01410-2There is no corresponding record for this reference.
- 8Smith, J. A.; Rosser, K. N.; Yagi, H.; Wallace, M. I.; May, P. W.; Ashfold, M. N. R. Diamond Deposition in a DC-arc Jet CVD System: Investigations of the Effects of Nitrogen Addition Diamond Relat. Mater. 2001, 10, 370– 375 DOI: 10.1016/S0925-9635(00)00444-18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjtFeltbc%253D&md5=42031dd16b270649b184172dd8543860Diamond deposition in a DC-arc Jet CVD system: investigations of the effects of nitrogen additionSmith, J. A.; Rosser, K. N.; Yagi, H.; Wallace, M. I.; May, P. W.; Ashfold, M. N. R.Diamond and Related Materials (2001), 10 (3-7), 370-375CODEN: DRMTE3; ISSN:0925-9635. (Elsevier Science S.A.)Studies of the CVD of diamond films at growth rates >100 μm h-1 with a 10-kW DC-arc jet system are described. Addns. of small amts. of N2 to the std. CH4/H2/Ar feedstock gas results in strong CN(B X) emission, and quenches C2(d a) and Hα emissions from the plasma. Species selective, spatially resolved optical emission measurements have enabled derivation of the longitudinal and lateral variation of emitting C2, CN radicals and H (n = 3) atoms within the plasma jet. SEM and laser Raman analyses indicate that N2 addns. also degrade both the growth rate and quality of the deposited diamond film; the latter technique also provides some evidence for N inclusion within the films.
- 9Truscott, B. S.; Kelly, M. W.; Potter, K. J.; Ashfold, M. N. R.; Mankelevich, Yu. A. Microwave Plasma Enhanced Chemical Vapour Deposition of Nitrogen Doped Diamond, II: CH4/N2/H2 Plasmas. J. Phys. Chem. A (awaiting submission).There is no corresponding record for this reference.
- 10Mankelevich, Yu. A.; Ashfold, M. N. R.; Ma, J. Plasma-chemical Processes in Microwave Plasma Enhanced Chemical Vapour Deposition Reactors Operating with C/H/Ar Gas Mixtures J. Appl. Phys. 2008, 104, 113304 DOI: 10.1063/1.303585010https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsFWitrzJ&md5=5ad12124fa9fa38815eb284be3c2f911Plasma-chemical processes in microwave plasma-enhanced chemical vapor deposition reactors operating with C/H/Ar gas mixturesMankelevich, Yuri A.; Ashfold, Michael N. R.; Ma, JieJournal of Applied Physics (2008), 104 (11), 113304/1-113304/11CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Microwave (MW) plasma-enhanced CVD (PECVD) reactors are widely used for growing diamond films with grain sizes spanning the range from nanometers through microns to millimeters. This paper presents a detailed description of a two-dimensional model of the plasma-chem. activation, transport, and deposition processes occurring in MW activated H/C/Ar mixts., focusing particularly on the following base conditions: 4.4%CH4/7%Ar/balance H2, pressure p = 150 torr, and input power P = 1.5 kW. The model results are verified and compared with a range of complementary exptl. data in the companion papers. These comparators include measured (by cavity ring down spectroscopy) C2(a), CH(X), and H(n = 2) column densities and C2(a) rotational temps., and IR (quantum cascade laser) measurements of C2H2 and CH4 column densities under a wide range of process conditions. The model allows identification of spatially distinct regions within the reactor that support net CH4 → C2H2 and C2H2 → CH4 conversions, and provide a detailed mechanistic picture of the plasma-chem. transformations occurring both in the hot plasma and in the outer regions. Semi-anal. expressions for estg. relative concns. of the various C1Hx species under typical MW PECVD conditions are presented, which support the consensus view regarding the dominant role of CH3 radicals in diamond growth under such conditions. (c) 2008 American Institute of Physics.
- 11Kelly, M. W.; Halliwell, S. C.; Rodgers, J.; Pattle, J. D.; Harvey, J. N.; Ashfold, M. N. R. Theoretical Investigations of the Reactions of N and O Containing Species on a C(100):H 2 × 1 Reconstructed Diamond Surface. J. Phys. Chem. A (awaiting submission).There is no corresponding record for this reference.
- 12Gordiets, B.; Ferreira, C. M.; Pinheiro, M. J.; Ricard, A. Self-consistent Kinetic Model of Low Pressure N2-H2 Flowing Discharges: I. Volume Processes Plasma Sources Sci. Technol. 1998, 7, 363– 378 DOI: 10.1088/0963-0252/7/3/01512https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXos1Whtw%253D%253D&md5=6528796615defecd8c173b8bc988971fSelf-consistent kinetic model of low-pressure N2-H2 flowing discharges: I. Volume processesGordiets, B.; Ferreira, C. M.; Pinheiro, M. J.; Ricard, A.Plasma Sources Science & Technology (1998), 7 (3), 363-378CODEN: PSTEEU; ISSN:0963-0252. (Institute of Physics Publishing)This work is the 1st of two companion papers devoted to the kinetic modeling of low-pressure d.c. flowing discharges in N2-H2 mixts. While the present paper is mainly concerned with bulk discharge processes, the 2nd one studies surface processes involving dissocd. N and H atoms, which are essential to understand the discharge properties. The global model combining bulk and surface processes as described in these two papers is self-contained in the sense that the sole input parameters it requires are those that can externally be chosen in expts., namely: total gas pressure, radius and length of the discharge tube, discharge current, gas flow rate and initial gas temp. and compn. (e.g., the relative hydrogen concn. X in the binary mixt. (1 - X)N2 + XH2 at the discharge inlet). For a given set of input parameters, this model enables one to calc. the following bulk plasma properties as a function of the axial coordinate z: concn. of N2, H2, NH, NH2, NH3 mols. and N, H atoms in the ground electronic state; population in the electronically excited states N2(A3Σu+, B3πg, a'πu-, a1πg, C3πu, a''Σg+), H2(R) (an effective high Rydberg state) and N(2D,2P); concn. of the ions N2+, N2+(B), N4+, H2+, H3+, HN2+ and H-; vibrational level populations of N2(X1Σg+) and H2(X1Σg+) mols.; electron d. Ne, mean kinetic energy 3/2kTe, characteristic energy uk and drift velocity vd; discharge sustaining elec. field E; av. gas temp. across the tube T and wall temp. Tw. The calcns. are compared with data from different expts. in pure N2 and H2 discharges (measurements of elec. field as a function of current and pressure) and in N2-H2 discharges (measurements of relative changes in the elec. field and the N2(C), N2+(B) concns. as a function of the H2 percentage). From the comparison to expt., rate coeffs. for associative ionization upon collisions between two excited N2 mols. and deactivation of N2(a') and N2(X, v) by H atoms were estd. from the model.
- 13Tatarova, E.; Dias, F. M.; Gordiets, B.; Ferriera, C. M. Molecular Dissociation in N2-H2 Microwave Discharges Plasma Sources Sci. Technol. 2005, 14, 19– 31 DOI: 10.1088/0963-0252/14/1/00313https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjtVKjsrk%253D&md5=6bda3e2fe3e3139b105975342f7da448Molecular dissociation in N2-H2 microwave dischargesTatarova, E.; Dias, F. M.; Gordiets, B.; Ferreira, C. M.Plasma Sources Science & Technology (2005), 14 (1), 19-31CODEN: PSTEEU; ISSN:0963-0252. (Institute of Physics Publishing)A microwave N2-H2 discharge driven by a traveling surface wave is investigated as a source of ground state N(4S) and H(1s) atoms. Exptl. investigations have been carried out in a plasma source operating at 2.45 GHz at low-pressure conditions (p = 0.5-2 torr). By means of optical emission spectroscopy and probe diagnostic techniques, the population densities of ground state atoms have been detected. The dissocn. kinetics is discussed in the framework of a theor. model based on a self-consistent treatment of the main discharge balances, wave electrodynamics and plasma-wall interactions. Electron-ion surface recombination processes involving HN+2 and N+2 ions are the most important sources of N(4S) gas phase atoms for the conditions considered. The relative no. of N(4S) atoms in respect to the total neutral d. remains approx. const. for percentages of H2 between 10% and 50% at nearly const. electron d. The competitive interplay of two important source channels of H(1s) atoms, namely electron impact dissocn. of H2 and H2 dissocn. via the quenching of nitrogen N2(a'1Σ-u) and N2 (A3 Σ+u) metastables, dets. a smooth decrease of hydrogen dissocn. when the amt. of hydrogen increases up to 50% in the mixt.
- 14van Helden, J. H.; Wagemans, W.; Yagci, G.; Zijlmans, R. A. B.; Schram, D. C.; Engeln, R.; Lombardi, G.; Stancu, G. D.; Röpcke, J. Detailed Studies of the Plasma-activated Catalytic Generation of Ammonia in N2-H2 Plasmas J. Appl. Phys. 2007, 101, 043305 DOI: 10.1063/1.2645828There is no corresponding record for this reference.
- 15van Helden, J. H.; van den Oever, P. J.; Kessels, W. M. M.; van de Sanden, M. C. M.; Schram, D. C.; Engeln, R. Production Mechanisms of NH and NH2 Radicals in N2-H2 Plasmas J. Phys. Chem. A 2007, 111, 11460– 11472 DOI: 10.1021/jp0727650There is no corresponding record for this reference.
- 16Ma, J.; Richley, J. C.; Ashfold, M. N. R.; Mankelevich, Yu.A. Probing the Plasma Chemistry in a Microwave Reactor used for Diamond Chemical Vapour Deposition by Cavity Ring Down Spectroscopy J. Appl. Phys. 2008, 104, 103305 DOI: 10.1063/1.302109516https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsVCktbvO&md5=817bef5ddba19c476d963ed666724743Probing the plasma chemistry in a microwave reactor used for diamond chemical vapor deposition by cavity ring down spectroscopyMa, Jie; Richley, James C.; Ashfold, Michael N. R.; Mankelevich, Yuri A.Journal of Applied Physics (2008), 104 (10), 103305/1-103305/9CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Abs. column densities of C2(a) and CH radicals and H(n = 2) atoms were measured in a diamond growing microwave reactor operating with hydrocarbon/Ar/H2 gas mixts. as functions of height (z) above the substrate surface and process conditions. The monitored species are each localized in the hot plasma region, where Tgas ∼ 3000 K, and their resp. column densities are each reproduced, quant., by 2-dimensional (r,z) modeling of the plasma chem. The H(n = 2) distribution is seen to peak nearer the substrate, reflecting its sensitivity both to thermal chem. (which drives the formation of ground state H atoms) and the distributions of electron d. (ne) and temp. (Te). All 3 column densities are sensitively dependent on the C/H ratio in the process gas mixt. but insensitive to the particular choice of hydrocarbon (CH4 and C2H2). The excellent agreement between measured and predicted column densities for all 3 probed species, under all process conditions studied, encourages confidence in the predicted no. densities of other of the more abundant radical species adjacent to the growing diamond surface which, in turn, reinforces the view that Me radicals are the dominant growth species in microwave activated hydrocarbon/Ar/H2 gas mixts. used in the CVD of microcryst. and single crystal diamond samples. (c) 2008 American Institute of Physics.
- 17Kelly, M. W.; Richley, J. C.; Western, C. M.; Ashfold, M. N. R.; Mankelevich, Yu. A. Exploring the Plasma Chemistry in Microwave Chemical Vapour Deposition of Diamond from C/H/O Gas Mixtures J. Phys. Chem. A 2012, 116, 9431– 9446 DOI: 10.1021/jp306190nThere is no corresponding record for this reference.
- 18Smith, J. A.; Wills, J. B.; Moores, H. S.; Orr-Ewing, A. J.; Ashfold, M. N. R.; Mankelevich, Yu.A.; Suetin, N. V. Effects of NH3 and N2 Additions to Hot Filament Activated CH4/H2 Gas Mixtures J. Appl. Phys. 2002, 92, 672– 681 DOI: 10.1063/1.148196118https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XkvFOqt78%253D&md5=548120ba8ad8d28cb569f98dcf6e2844Effects of NH3 and N2 additions to hot filament activated CH4/H2 gas mixturesSmith, James A.; Wills, Jonathan B.; Moores, Helen S.; Orr-Ewing, Andrew J.; Ashfold, Michael N. R.; Mankelevich, Yuri A.; Suetin, Nikolay V.Journal of Applied Physics (2002), 92 (2), 672-681CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Resonance enhanced multiphoton ionization and cavity ring down spectroscopies were used to provide spatially resolved measurements of relative H atom and CH3 radical no. densities, and NH column densities, in a hot filament (HF) reactor designed for diamond CVD and here operating with a 1% CH4/n/H2 gas mixt.-where n represents defined addns. of N2 or NH3. Three-dimensional modeling of the H/C/N chem. prevailing in such HF activated gas mixts. allows the relative no. d. measurements to be placed on an abs. scale. Expt. and theory both indicate that N2 is largely unreactive under the prevailing exptl. conditions, but NH3 addns. have a major effect on the gas phase chem. and compn. Specifically, NH3 addns. introduce an addnl. series of H-shift reactions NHx+H[rlhar2]NHx-1+H2 which gave N atoms with calcd. steady state no. densities >1013 cm-3 in the case of 1% NH3 addns. in the hotter regions of the reactor. These react, irreversibly, with C1 hydrocarbon species forming HCN products, thereby reducing the concn. of free hydrocarbon species (notably CH3) available to participate in diamond growth. The deduced redn. in CH3 no. d. due to competing gas phase chem. is compounded by NH3 induced modifications to the hot filament surface, which reduce its efficiency as a catalyst for H2 dissocn., thus lowering the steady state gas phase H atom concns. and the extent and efficiency of all subsequent gas phase transformations.
- 19Ma, J.; Ashfold, M. N. R.; Mankelevich, Yu. A. Validating Optical Emission Spectroscopy as a Diagnostic of Microwave Activated CH4/Ar/H2 Plasmas used for Diamond Chemical Vapor Deposition J. Appl. Phys. 2009, 105, 043302 DOI: 10.1063/1.307803219https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitlamurk%253D&md5=dadb1e77b273c4085bad7f56b31485b7Validating optical emission spectroscopy as a diagnostic of microwave activated CH4/Ar/H2 plasmas used for diamond chemical vapor depositionMa, Jie; Ashfold, Michael N. R.; Mankelevich, Yuri A.Journal of Applied Physics (2009), 105 (4), 043302/1-043302/12CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Spatially resolved optical emission spectroscopy (OES) was used to study the gas phase chem. and compn. in a microwave activated CH4/Ar/H2 plasma operating at moderate power densities (∼30 W cm-3) and pressures (≤175 torr) during CVD of polycryst. diamond. Several tracer species were monitored to gain information about the plasma. Relative concns. of ground state H (n = 1) atoms were detd. by actinometry, and the validity of this method were demonstrated for the present exptl. conditions. Electronically excited H (n = 3 and 4) atoms, Ar (4p) atoms, and C2 and CH radicals were studied also, by monitoring their emissions as functions of process parameters (Ar and CH4 flow rates, input power, and pressure) and of distance above the substrate. These various species exhibit distinctive behaviors, reflecting their different formation mechanisms. Relative trends identified by OES are in very good agreement with those revealed by complementary abs. absorption measurements (using cavity ring down spectroscopy) and with the results of complementary two-dimensional modeling of the plasma chem. prevailing within this reactor. (c) 2009 American Institute of Physics.
- 20Brazier, C. R.; Ram, R. S.; Bernath, P. F. Fourier Transform Spectroscopy of the A3Π–X3Σ– Transition of NH J. Mol. Spectrosc. 1986, 120, 381– 402 DOI: 10.1016/0022-2852(86)90012-3There is no corresponding record for this reference.
- 21Fairchild, P. W.; Smith, G. P.; Crosley, D. R.; Jeffries, J. B. Lifetimes and Transition Probabilities for NH(A3Πi – X3Σ–) Chem. Phys. Lett. 1984, 107, 181– 186 DOI: 10.1016/0009-2614(84)85696-1There is no corresponding record for this reference.
- 22Owono Owono, L. C.; Ben Abdallah, D.; Jaidane, N.; Ben Lakhdar, Z. Theoretical Radiative Properties Between States of the Triplet Manifold of NH Radical J. Chem. Phys. 2008, 128, 084309 DOI: 10.1063/1.2884923There is no corresponding record for this reference.
- 23Western, C. M. PGOPHER, a Program for Simulating Rotational Structure; University of Bristol, http://pgopher.chm.bris.ac.uk.There is no corresponding record for this reference.
- 24Roux, F.; Michaud, F.; Vervloet, M. High-Resolution Fourier Spectrometry of 14N2 Violet Emission Spectrum: Extensive Analysis of the C3Πu→B3Πg System J. Mol. Spectrosc. 1993, 158, 270– 277 DOI: 10.1006/jmsp.1993.1071There is no corresponding record for this reference.
- 25Gilmore, F. R.; Laher, R. R.; Espy, P. J. Franck-Condon Factors, r-Centroids, Electronic Transition Moments, and Einstein Coefficients for Many Nitrogen and Oxygen Band Systems J. Phys. Chem. Ref. Data 1992, 21, 1005– 1107 DOI: 10.1063/1.555910There is no corresponding record for this reference.
- 26Plemmons, D. H.; Parigger, C.; Lewis, J. W. L.; Hornkohl, J. O. Analysis of Combined Spectra of NH and N2 Appl. Opt. 1998, 37, 2493– 2498 DOI: 10.1364/AO.37.00249326https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXivVSlsrY%253D&md5=42a042405abc9ea0e837f987af1e6f18Analysis of combined spectra of NH and N2Plemmons, David H.; Parigger, Christian; Lewis, James W. L.; Hornkohl, James O.Applied Optics (1998), 37 (12), 2493-2498CODEN: APOPAI; ISSN:0003-6935. (Optical Society of America)Gas phase diagnostics with multispecies diat. spectra is discussed. Analyses of spectra from the A3Πi ↔ X3Σ- system of NH and the C3Πu ↔ B3Πg 2nd-pos. system of N2 are presented. Multispecies spectroscopy is applied to exptl. spectra obtained from laser-induced breakdown plasmas in anhyd. NH3 gas and a low-pressure discharge lamp.
- 27Kramida, A.; Ralchenko, Yu.; Reader, J.; NIST ASD Team. NIST Atomic Spectra Database (version 5.2), [Online]; National Institute of Standards and Technology: Gaithersburg, MD, 2014; available athttp://physics.nist.gov/asd (Tuesday, 28-Apr-2015 04:49:32 EDT).There is no corresponding record for this reference.
- 28Moore, C. E.Selected Tables of Atomic Spectra, Atomic Energy Levels and Multiplet Tables–N I, N II, N III; National Standard Reference Data Series (United States National Bureau of Standards); 1975, document 3, section 5.There is no corresponding record for this reference.
- 29Tachiev, G. I.; Froese Fischer, C. Breit-Pauli Energy Levels and Transition Rates for Nitrogen-like and Oxygen-like Sequences Astron. Astrophys. 2002, 385, 716– 723 DOI: 10.1051/0004-6361:2001181629https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XktV2lur4%253D&md5=8a829749533395b1dc6b19897f731101Breit-Pauli energy levels and transition rates for nitrogen-like and oxygen-like sequencesTachiev, G. I.; Fischer, C. FroeseAstronomy and Astrophysics (2002), 385 (2), 716-723CODEN: AAEJAF; ISSN:0004-6361. (EDP Sciences)Breit-Pauli results for energy levels, lifetimes, and Lande gJ factors were detd. for all levels up to 2p23d of the N-like sequence (Z = 7-17) and 2p33d of the O-like sequence (Z = 8-20). Exceptions are some lower members of the sequence where the spectrum included only those levels below the second 2p24s term in the case of N-like or 2p34s in the case of O-like. The computed energy and E1, E2, M1, M2 transition data between all levels, including convergence of the LS line strength for both length and velocity forms, may be viewed at a website. Critically evaluated transition data is presented for N I, O II, Mg VI, and Si VIII (N-like sequence) and O I, Ne III, Mg V, and Si VII (O-like) for E1 transitions including uncertainty ests. The accuracy of energy levels is detd. by comparison with expt. Transition rates with uncertainties are compared with expt. and other theory.
- 30
An assumption that the kinetics of the N(2p23p1) states with energies ≈12 eV (i.e., excitation by EI balanced by radiative decay) resemble those of H(n = 3) allows the following order-of-magnitude estimate of the N(2p23p1) concentration under base conditions: [N(2p23p1)] ∼ [N(2p3)] × [H(n = 3)]/[H(n = 1)] ≈ 200 cm–3 given typical calculated values for the [H(n = 3)]/[H(n = 1)] ratio (≈2 × 10–10) and the concentration of ground state nitrogen atoms ([N(2p3)] < 1012 cm–3) in the plasma core (see section 4).
There is no corresponding record for this reference. - 31Ma, J.; Richley, J. C.; Davies, D. R. W.; Cheesman, A.; Ashfold, M. N. R.; Mankelevich, Yu. A. Spectroscopic and Modelling Investigations of the Gas Phase Chemistry and Composition in Microwave Plasma Activated B2H6/Ar/H2 Gas Mixtures J. Phys. Chem. A 2010, 114, 2447– 2463 DOI: 10.1021/jp9094694There is no corresponding record for this reference.
- 32Smith, G. P.; Golden, D. M.; Frenklach, M.; Moriarty, N. W.; Eiteneer, B.; Goldenberg, M.; Bowman, C. T.; Hanson, R. K.; Song, S.; Gardiner, W. C.; GRI-Mech 3.0; http://www.me.berkeley.edu/gri_mech/.There is no corresponding record for this reference.
- 33Davidson, D. F.; Kohse-Hoinghaus, K.; Chang, A. Y.; Hanson, R. K. A Pyrolysis Mechanism for Ammonia Int. J. Chem. Kinet. 1990, 22, 513– 535 DOI: 10.1002/kin.55022050833https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXksVOgsLg%253D&md5=078292afae6b8d9b33aef497d834b7ffA pyrolysis mechanism for ammoniaDavidson, D. F.; Kohse-Hoeinghaus, K.; Chang, A. Y.; Hanson, R. K.International Journal of Chemical Kinetics (1990), 22 (5), 513-35CODEN: IJCKBO; ISSN:0538-8066.The mechanism of NH3 pyrolysis was investigated over a wide range of conditions behind reflected shock waves. Quant. time-history measurements of the species NH and NH2 were made by using narrow-linewidth laser absorption. Rate coeffs. for several reactions which influence the NH and NH2 profiles were fitted in the temp. range 2200-2800 K. The reaction and the corresponding best fit rate coeffs. are as follows: NH2 + H → NH + H2 with a rate coeff. of 4.0 × 1013 exp(-3650/RT) cm3 mol-1 s-1, NH2 + NH → N2H2 + H with a rate coeff. of 1.5 × 1015T-0.5 cm3 mol-3 s-1. The temp. dependences of these rate coeffs. are based on previous ests. The exptl. data from 4 earlier measurements of the dissocn. reaction NH3 + M → NH2 + H + M were reanalyzed in light of recent data for the rate of NH3 + H → NH2 + H2, and an improved rate coeff. of 2.2 × 1016 exp(-93470/RT) cm3 mol-1 s-1 as 1740-3300 K was obtained.
- 34Dean, A. M.; Bozzelli, J. W. Combustion Chemistry of Nitrogen. In Gas Phase Combustion Chemistry; Gardiner, W. C., Ed.; Springer-Verlag: New York, 2000; Chapter 2.There is no corresponding record for this reference.
- 35Millar, T. J.; Farquhar, P. R. A.; Willacy, P. K. The UMIST Database for Astrochemistry 1995 Astron. Astrophys., Suppl. Ser. 1997, 121, 139– 185 DOI: 10.1051/aas:199711835https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXhtVCjtb0%253D&md5=4b62600063c77bafb7c8cc4956688f63The UMIST database for astrochemistry 1995Millar, T.J.; Farquhar, P.R.A.; Willacy, K.Astronomy & Astrophysics, Supplement Series (1997), 121 (1), 139-185CODEN: AAESB9; ISSN:0365-0138. (Editions de Physique)We report the release of a new version of the UMIST database for astrochem. The database contains the rate coeffs. of 3864 gas-phase reactions important in interstellar and circumstellar chem. and involves 395 species and 12 elements. The previous (1990) version of this database has been widely used by modellers. In addn. to the rate coeffs., we also tabulate permanent elec. dipole moments of the neutral species and heats of formation. A numerical model of the chem. evolution of a dark cloud is calcd. and important differences to that calcd. with the previous database noted.
- 36Richley, J. C.; Fox, O. J. L.; Ashfold, M. N. R.; Mankelevich, Yu. A. Combined Experimental and Modelling Studies of Microwave Activated CH4/H2/Ar Plasmas for Microcrystalline, Nanocrystalline, and Ultrananocrystalline Diamond Deposition J. Appl. Phys. 2011, 109, 063307 DOI: 10.1063/1.356218536https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjvVWkurw%253D&md5=5c718c66e390e582efc8c32363ae8c38Combined experimental and modeling studies of microwave activated CH4/H2/Ar plasmas for microcrystalline, nanocrystalline, and ultrananocrystalline diamond depositionRichley, James C.; Fox, Oliver J. L.; Ashfold, Michael N. R.; Mankelevich, Yuri A.Journal of Applied Physics (2011), 109 (6), 063307/1-063307/14CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)A comprehensive study of microwave (MW) activated CH4/H2/Ar plasmas used for diamond CVD is reported, focusing particularly on the effects of gross variations in the H2/Ar ratio in the input gas mixt. (from H2/Ar mole fraction ratios of > 10:1, through to ∼1:99). Abs. column densities of C2(a) and CH(X) radicals and of H(n = 2) atoms were detd. by cavity ringdown spectroscopy, as functions of height (z) above a substrate and of process conditions (CH4, H2, and Ar input mole fractions, total pressure, p, and input microwave power, P). Optical emission spectroscopy was also used to explore the relative densities of electronically excited H atoms, and CH, C2, and C3 radicals, as functions of these same process conditions. These exptl. data are complemented by extensive 2D (r, z) modeling of the plasma chem., which provides a quant. rationale for all of the exptl. observations. Progressive replacement of H2 by Ar (at const. p and P) leads to an expanded plasma vol. Under H2-rich conditions, > 90% of the input MW power is absorbed through rovibrational excitation of H2. Reducing the H2 content (as in an Ar-rich plasma) leads to a redn. in the absorbed power d.; the plasma necessarily expands to accommodate a given input power. The av. power d. in an Ar-rich plasma is much lower than that in an H2-rich plasma operating at the same p and P. Progressive replacement of H2 by Ar is shown also to result in an increased electron temp., an increased H/H2 no. d. ratio, but little change in the max. gas temp. in the plasma core (which is consistently ∼3000 K). Given the increased H/H2 ratio, the fast H-shifting (CyHx + H ↔ CyHx-1 + H2; y = 1-3) reactions ensure that the core of Ar-rich plasma contains much higher relative abundances of "product" species like C atoms, and C2, and C3 radicals. The effects of Ar diln. on the absorbed power dissipation pathways and the various species concns. just above the growing diamond film are also investigated and discussed. (c) 2011 American Institute of Physics.
- 37Guerra, V.; Sa, P. A.; Loureiro, J. Kinetic Modelling of Low-Pressure Nitrogen Discharges and Post-Discharges Eur. Phys. J.: Appl. Phys. 2004, 28, 125– 152 DOI: 10.1051/epjap:200418837https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvFOrug%253D%253D&md5=ec12ecef6296eb5052cc7d398dc234f2Kinetic modeling of low-pressure nitrogen discharges and post-dischargesGuerra, V.; Sa, P. A.; Loureiro, J.European Physical Journal: Applied Physics (2004), 28 (2), 125-152CODEN: EPAPFV; ISSN:1286-0042. (EDP Sciences)A review. The kinetic modeling of low-pressure (p ∼ 1-10 torr) stationary nitrogen discharges and the corresponding afterglows is reviewed. It is shown that a good description of the overall behavior of nitrogen plasmas requires a deep understanding of the coupling between different kinetics. The central role is played by ground-state vibrationally excited mols., N2(X 1Σ+g, ν), which have a strong influence on the shape of the electron energy distribution function, on the creation and destruction of electronically excited states, on the gas heating, dissocn. and on afterglow emissions. N2(X 1Σ+g, ν) mols. are actually the hinge ensuring a strong link between the various kinetics. The noticeable task done by electronically excited metastable mols., in particular N2(A 3Σ+u) and N2(α' Σ-u), is also pointed out. Besides contributing to the same phenomena as vibrationally excited mols., these electronic metastable states play also a categorical role in ionization. Furthermore, vibrationally excited mols. in high ν levels are in the origin of the peaks obsd. in the flowing afterglow for the concns. of several species, such as N2(A 3Σ+g), N2(B 3Πg), N2+(B 2Σ-u) and electrons, which occur downstream from the discharge after a dark zone as a consequence of the V-V pumping-up mechanism.
- 38Hack, W.; Kurzke, H.; Ottinger, Ch.; Wagner, H. Gg. Elementary Reactions of Electronically Excited N2 in the 3Σ+u State with H2 and NH3 Chem. Phys. 1988, 126, 111– 124 DOI: 10.1016/0301-0104(88)85024-9There is no corresponding record for this reference.
- 39Herron, J. T. Evaluated Chemical Kinetics Data for Reactions of N(2D), N(2P) and N2(A3Σ+u) in the Gas Phase J. Phys. Chem. Ref. Data 1999, 28, 1453– 1483DOI: 10.1063/1.556043
and references therein
There is no corresponding record for this reference. - 40Slanger, T. G.; Wood, B. J.; Black, G. Temperature Dependent N2(A3Σ+u) Quenching Rate Coefficients J. Photochem. 1973, 2, 63– 66 DOI: 10.1016/0047-2670(73)80005-X40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE3sXlt1Sjur0%253D&md5=89fec63e53394d67761de20396eb92baTemperature-dependent molecular nitrogen (A3 σ+u) quenching rate coefficientsSlanger, T. G.; Wood, B. J.; Black, G.Journal of Photochemistry (1973), 2 (1), 63-6CODEN: JPCMAE; ISSN:0047-2670.The reactions of N2(A3Σ+u) with 6 different quenching gases (N2O, O2, CO, C2H6, CH4, and H2) are studied at various temps. N2 (A) mols. are produced by photolysis of N2O at 1470 Å. N2 (A) mols. are detected by chemiluminescence (NO (γ)-bend signal) following NO addn. The rate coeffs. at different temps., the activation energy, and the log of the preexponential factor are calcd. and discussed. The rate coeffs. at 300°K are compared with those of Callear and Wood (1971) and Setser, et al. (1971). Agreement is good for those species that have quenching coeffs. faster than 5 × 1011 cm3/mol.-sec.
- 41Pancheshnyi, S. V.; Starikovskaia, S. M.; Starikovskii, A. Yu. Collisional Deactivation of N2(C3Πu, v = 0, 1, 2, 3) States by N2, O2, H2 and H2O Molecules Chem. Phys. 2000, 262, 349– 357 DOI: 10.1016/S0301-0104(00)00338-4There is no corresponding record for this reference.
- 42Adam, L.; Hack, W.; Zhu, H.; Qu, Z.-W.; Schinke, R. Experimental and Theoretical Investigation of the Reaction NH(X3Σ–) + H(2S) → N(4S) + H2(X1S+g) J. Chem. Phys. 2005, 122, 114301 DOI: 10.1063/1.1862615There is no corresponding record for this reference.
- 43Ho, G. H.; Golde, M. F. Experimental Study of the Reactions of N2(A3Σ+u) with H Atoms and OH Radicals J. Chem. Phys. 1991, 95, 8866– 8870 DOI: 10.1063/1.461219There is no corresponding record for this reference.